diff --git a/dist/index.js b/dist/index.js
index 0319f35..885a0c2 100644
Binary files a/dist/index.js and b/dist/index.js differ
diff --git a/src/install-pnpm/run.ts b/src/install-pnpm/run.ts
index 0c20f6d..6499130 100644
--- a/src/install-pnpm/run.ts
+++ b/src/install-pnpm/run.ts
@@ -101,8 +101,8 @@ Remove one of these versions to avoid version mismatch errors like ERR_PNPM_BAD_
   }
 
   if (typeof packageManager === 'string' && packageManager.startsWith('pnpm@')) {
-    // pnpm will handle version management via packageManager field
-    return undefined
+    // Strip the "pnpm@" prefix and any "+sha..." hash suffix
+    return packageManager.replace('pnpm@', '').replace(/\+.*$/, '')
   }
 
   if (!GITHUB_WORKSPACE) {