diff --git a/.github/workflows/test-smokes.yml b/.github/workflows/test-smokes.yml
index 501ee581623..f5bc8749093 100644
--- a/.github/workflows/test-smokes.yml
+++ b/.github/workflows/test-smokes.yml
@@ -117,10 +117,16 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-playwright-
 
+      - name: Install Playwright system dependencies
+        if: ${{ runner.os != 'Windows' || github.event_name == 'schedule' }}
+        timeout-minutes: 15
+        run: npx playwright install-deps
+        working-directory: ./tests/integration/playwright
+
       - name: Install Playwright Browsers
         if: ${{ runner.os != 'Windows' || github.event_name == 'schedule' }}
-        timeout-minutes: 10
-        run: npx playwright install --with-deps
+        timeout-minutes: 15
+        run: npx playwright install
         working-directory: ./tests/integration/playwright
 
       - name: Install MECA validator
diff --git a/news/changelog-1.10.md b/news/changelog-1.10.md
index e9f6a320ad3..b8fcb720ae8 100644
--- a/news/changelog-1.10.md
+++ b/news/changelog-1.10.md
@@ -73,4 +73,5 @@ All changes included in 1.10:
 - ([#14445](https://github.com/quarto-dev/quarto-cli/issues/14445)): Fix intermittent `Uncaught (in promise) TypeError: Writable stream is closed or errored.` aborting renders on Linux. `execProcess` now awaits and swallows the rejection from `process.stdin.close()` when the child closes its stdin first. The captured stderr is now also surfaced when `typst-gather analyze` falls back to staging all packages, so failures are diagnosable without bypassing `quarto`.
 - ([#14359](https://github.com/quarto-dev/quarto-cli/issues/14359)): Fix intermediate `.quarto_ipynb` file not being deleted after rendering a `.qmd` with Jupyter engine, causing numbered variants (`_1`, `_2`, ...) to accumulate on disk across renders.
 - ([#14461](https://github.com/quarto-dev/quarto-cli/issues/14461)): Fix `quarto render --to pdf` aborting with `ERROR: Problem running 'fmtutil-sys --all' to rebuild format tree.` when an automatically-installed LaTeX package's post-update format rebuild fails. Format-tree rebuild is now treated as best-effort housekeeping (matching upstream `tinytex` R behavior) — the failure is logged as a warning and the package install completes.
-- ([#14472](https://github.com/quarto-dev/quarto-cli/issues/14472)): Add support for Kotlin in code annotations and YAML cell options. (author: @barendgehrels)
\ No newline at end of file
+- ([#14472](https://github.com/quarto-dev/quarto-cli/issues/14472)): Add support for Kotlin in code annotations and YAML cell options. (author: @barendgehrels)
+- ([#14529](https://github.com/quarto-dev/quarto-cli/issues/14529)): Fix bundled Julia engine path leaking into rendered YAML metadata and pandoc log output when running an installed Quarto. The internal subtree-engine filter only matched the source-tree share-path layout (`resources/extension-subtrees/`) and missed installed layouts where the path is `share/extension-subtrees/`.
\ No newline at end of file
diff --git a/src/command/render/pandoc.ts b/src/command/render/pandoc.ts
index a9e7ff3dc27..6df97871aa9 100644
--- a/src/command/render/pandoc.ts
+++ b/src/command/render/pandoc.ts
@@ -59,6 +59,7 @@ import {
   metadataGetDeep,
 } from "../../config/metadata.ts";
 import { pandocBinaryPath, resourcePath } from "../../core/resources.ts";
+import { filterBundledSubtreeEngines } from "../../extension/extension.ts";
 import { pandocAutoIdentifier } from "../../core/pandoc/pandoc-id.ts";
 import {
   partitionYamlFrontMatter,
@@ -439,15 +440,9 @@ export async function runPandoc(
     // This can cause issue on regex test for printed output
     cleanQuartoTestsMetadata(metadata);
 
-    // Filter out bundled engines from the engines array
+    // Filter out bundled engines from the engines array (#14529)
     if (Array.isArray(metadata.engines)) {
-      const filteredEngines = metadata.engines.filter((engine) => {
-        const enginePath = typeof engine === "string" ? engine : engine.path;
-        // Keep user engines, filter out bundled ones
-        return !enginePath?.replace(/\\/g, "/").includes(
-          "resources/extension-subtrees/",
-        );
-      });
+      const filteredEngines = filterBundledSubtreeEngines(metadata.engines);
 
       // Remove the engines key entirely if empty, otherwise assign filtered array
       if (filteredEngines.length === 0) {
@@ -1323,15 +1318,11 @@ export async function runPandoc(
   // and it breaks ensureFileRegexMatches
   cleanQuartoTestsMetadata(pandocPassedMetadata);
 
-  // Filter out bundled engines from metadata passed to Pandoc
+  // Filter out bundled engines from metadata passed to Pandoc (#14529)
   if (Array.isArray(pandocPassedMetadata.engines)) {
-    const filteredEngines = pandocPassedMetadata.engines.filter((engine) => {
-      const enginePath = typeof engine === "string" ? engine : engine.path;
-      if (!enginePath) return true;
-      return !enginePath.replace(/\\/g, "/").includes(
-        "resources/extension-subtrees/",
-      );
-    });
+    const filteredEngines = filterBundledSubtreeEngines(
+      pandocPassedMetadata.engines,
+    );
 
     if (filteredEngines.length === 0) {
       delete pandocPassedMetadata.engines;
diff --git a/src/extension/extension.ts b/src/extension/extension.ts
index 4dfdbddd1d0..eb5674e9c2f 100644
--- a/src/extension/extension.ts
+++ b/src/extension/extension.ts
@@ -28,6 +28,7 @@ import { Metadata, QuartoFilter } from "../config/types.ts";
 import {
   kSkipHidden,
   normalizePath,
+  pathWithForwardSlashes,
   resolvePathGlobs,
   safeExistsSync,
 } from "../core/path.ts";
@@ -710,6 +711,39 @@ export function builtinSubtreeExtensions() {
   return resourcePath("extension-subtrees");
 }
 
+// Predicate: does `enginePath` live under the built-in subtree path?
+// Works in both source-tree (QUARTO_SHARE_PATH=src/resources) and
+// installed (QUARTO_SHARE_PATH=share) layouts. See #14529.
+// Uses a path-boundary check so a sibling directory whose name merely
+// starts with the same prefix (e.g. `extension-subtrees-custom/`) does
+// not register as bundled.
+export function isBundledSubtreeEnginePath(
+  enginePath: string,
+  subtreePath: string,
+): boolean {
+  const normalizedEngine = pathWithForwardSlashes(enginePath);
+  const normalizedSubtree = pathWithForwardSlashes(subtreePath).replace(
+    /\/+$/,
+    "",
+  );
+  return normalizedEngine === normalizedSubtree ||
+    normalizedEngine.startsWith(normalizedSubtree + "/");
+}
+
+// Filters out bundled subtree engines from a metadata `engines` array.
+export function filterBundledSubtreeEngines(
+  engines: ReadonlyArray<unknown>,
+): unknown[] {
+  const subtreePath = builtinSubtreeExtensions();
+  return engines.filter((engine) => {
+    const enginePath = typeof engine === "string"
+      ? engine
+      : (engine as { path?: string } | null | undefined)?.path;
+    if (!enginePath) return true;
+    return !isBundledSubtreeEnginePath(enginePath, subtreePath);
+  });
+}
+
 // Validate the extension
 function validateExtension(extension: Extension) {
   let contribCount = 0;
diff --git a/tests/docs/smoke-all/2025/12/22/markdown-engine-no-extension-subtrees.qmd b/tests/docs/smoke-all/2025/12/22/markdown-engine-no-extension-subtrees.qmd
index aeec583796b..ebfa6ca29d4 100644
--- a/tests/docs/smoke-all/2025/12/22/markdown-engine-no-extension-subtrees.qmd
+++ b/tests/docs/smoke-all/2025/12/22/markdown-engine-no-extension-subtrees.qmd
@@ -6,7 +6,7 @@ _quarto:
     html:
       printsMessage:
         level: INFO
-        regex: 'resources[/\\]extension-subtrees[/\\]'
+        regex: 'extension-subtrees[/\\]'
         negate: true
 ---
 
diff --git a/tests/unit/extension/filter-bundled-engines.test.ts b/tests/unit/extension/filter-bundled-engines.test.ts
new file mode 100644
index 00000000000..ecc0764fb88
--- /dev/null
+++ b/tests/unit/extension/filter-bundled-engines.test.ts
@@ -0,0 +1,122 @@
+/*
+ * filter-bundled-engines.test.ts
+ *
+ * Tests that bundled subtree engines are filtered out of metadata
+ * regardless of the share path layout (source tree vs installed).
+ * Related to issue #14529.
+ *
+ * Copyright (C) 2026 Posit Software, PBC
+ */
+
+import { unitTest } from "../../test.ts";
+import { assert, assertEquals } from "testing/asserts";
+import {
+  builtinSubtreeExtensions,
+  filterBundledSubtreeEngines,
+  isBundledSubtreeEnginePath,
+} from "../../../src/extension/extension.ts";
+import { join } from "../../../src/deno_ral/path.ts";
+
+unitTest(
+  "isBundledSubtreeEnginePath - source-tree share path",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath = "/repo/src/resources/extension-subtrees";
+    const enginePath =
+      "/repo/src/resources/extension-subtrees/julia-engine/_extensions/julia-engine/julia-engine.js";
+    assert(isBundledSubtreeEnginePath(enginePath, subtreePath));
+  },
+);
+
+unitTest(
+  "isBundledSubtreeEnginePath - installed POSIX share path (#14529)",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath = "/usr/local/share/quarto/extension-subtrees";
+    const enginePath =
+      "/usr/local/share/quarto/extension-subtrees/julia-engine/_extensions/julia-engine/julia-engine.js";
+    assert(isBundledSubtreeEnginePath(enginePath, subtreePath));
+  },
+);
+
+unitTest(
+  "isBundledSubtreeEnginePath - installed Windows share path (#14529)",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath =
+      "C:\\Users\\me\\scoop\\apps\\quarto\\current\\share\\extension-subtrees";
+    const enginePath =
+      "C:\\Users\\me\\scoop\\apps\\quarto\\current\\share\\extension-subtrees\\julia-engine\\_extensions\\julia-engine\\julia-engine.js";
+    assert(isBundledSubtreeEnginePath(enginePath, subtreePath));
+  },
+);
+
+unitTest(
+  "isBundledSubtreeEnginePath - user-supplied engine path is not bundled",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath = "/usr/local/share/quarto/extension-subtrees";
+    const userEnginePath = "/home/me/project/_extensions/myext/my-engine.js";
+    assert(!isBundledSubtreeEnginePath(userEnginePath, subtreePath));
+  },
+);
+
+unitTest(
+  "isBundledSubtreeEnginePath - sibling directory sharing prefix is not bundled",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath = "/usr/local/share/quarto/extension-subtrees";
+    const siblingPath =
+      "/usr/local/share/quarto/extension-subtrees-custom/foo/_extensions/foo/foo.js";
+    assert(!isBundledSubtreeEnginePath(siblingPath, subtreePath));
+  },
+);
+
+unitTest(
+  "isBundledSubtreeEnginePath - Windows sibling directory sharing prefix is not bundled",
+  // deno-lint-ignore require-await
+  async () => {
+    const subtreePath =
+      "C:\\Users\\me\\scoop\\apps\\quarto\\current\\share\\extension-subtrees";
+    const siblingPath =
+      "C:\\Users\\me\\scoop\\apps\\quarto\\current\\share\\extension-subtrees-custom\\foo\\_extensions\\foo\\foo.js";
+    assert(!isBundledSubtreeEnginePath(siblingPath, subtreePath));
+  },
+);
+
+unitTest(
+  "filterBundledSubtreeEngines - drops bundled julia-engine in current env",
+  // deno-lint-ignore require-await
+  async () => {
+    // Build a path that matches the resolved built-in subtree location,
+    // so the test exercises the real path the production code sees.
+    const bundled = {
+      path: join(
+        builtinSubtreeExtensions(),
+        "julia-engine",
+        "_extensions",
+        "julia-engine",
+        "julia-engine.js",
+      ),
+    };
+    const userEngine = {
+      path: "/home/me/project/_extensions/myext/my-engine.js",
+    };
+    assertEquals(
+      filterBundledSubtreeEngines([bundled, userEngine, "julia"]),
+      [userEngine, "julia"],
+    );
+  },
+);
+
+unitTest(
+  "filterBundledSubtreeEngines - keeps string engines and engines with no path",
+  // deno-lint-ignore require-await
+  async () => {
+    const noPath = { name: "something" } as unknown;
+    assertEquals(
+      filterBundledSubtreeEngines(["julia", "jupyter", noPath]),
+      ["julia", "jupyter", noPath],
+    );
+  },
+);