diff --git a/src/extract/resolve/module-classifiers.mjs b/src/extract/resolve/module-classifiers.mjs
index 6a4c7e45a..ee600b788 100644
--- a/src/extract/resolve/module-classifiers.mjs
+++ b/src/extract/resolve/module-classifiers.mjs
@@ -168,8 +168,15 @@ function isWorkspaceAliased(pModuleName, pResolvedModuleName, pManifest) {
     // oh and: ```picomatch.isMatch('asdf', 'asdf/**') === true``` so
     // in case it's only 'asdf' that's in the resolved module name for some reason
     // we're good as well.
+    //
+    // workspaces is supposed to be array of strings, where each string is
+    // a glob pattern. However, in the field there's occasions where it's
+    // not a string. We'll just ignore those for now, hence the presence of
+    // the `typeof pWorkspace === "string"` check.
     const lModuleFriendlyWorkspaceGlobs = lWorkspaces.map((pWorkspace) =>
-      pWorkspace.endsWith("/") ? `${pWorkspace}**` : `${pWorkspace}/**`,
+      typeof pWorkspace === "string" && pWorkspace.endsWith("/")
+        ? `${pWorkspace}**`
+        : `${pWorkspace}/**`,
     );
     if (picomatch.isMatch(pResolvedModuleName, lModuleFriendlyWorkspaceGlobs)) {
       return true;
diff --git a/test/extract/resolve/module-classifiers.get-alias-types.spec.mjs b/test/extract/resolve/module-classifiers.get-alias-types.spec.mjs
index 52ca0157d..2dbef29c8 100644
--- a/test/extract/resolve/module-classifiers.get-alias-types.spec.mjs
+++ b/test/extract/resolve/module-classifiers.get-alias-types.spec.mjs
@@ -293,6 +293,44 @@ describe("[I] extract/resolve/module-classifiers - getAliasTypes", () => {
     );
   });
 
+  it("doesn't run aliased and aliased-workspace for when workspaces is an array, but the entry isn't a string", () => {
+    const lManifest = {
+      name: "test",
+      version: "1.0.0",
+      dependencies: {},
+      workspaces: [{ "packages/*": "packages/*" }],
+    };
+    const lResolveOptions = {};
+    deepEqual(
+      getAliasTypes(
+        "some-workspaced-local-package",
+        "packages/a-package/index.js",
+        lResolveOptions,
+        lManifest,
+      ),
+      [],
+    );
+  });
+
+  it("skips over entries in the workspaces array that aren't string, but still uses the rest", () => {
+    const lManifest = {
+      name: "test",
+      version: "1.0.0",
+      dependencies: {},
+      workspaces: [{ "packages/*": "packages/*" }, "packages/*"],
+    };
+    const lResolveOptions = {};
+    deepEqual(
+      getAliasTypes(
+        "some-workspaced-local-package",
+        "packages/a-package/index.js",
+        lResolveOptions,
+        lManifest,
+      ),
+      ["aliased", "aliased-workspace"],
+    );
+  });
+
   it("classifies as a webpack alias if it could be both a webpack alias _and_ a workspace alias", () => {
     const lManifest = {
       name: "test",