diff --git a/.github/workflows/matrix.yml b/.github/workflows/matrix.yml
index 2bb700c4ece63..f5146912f16af 100644
--- a/.github/workflows/matrix.yml
+++ b/.github/workflows/matrix.yml
@@ -9,9 +9,10 @@ on:
     - master
 
 # We only care about the latest revision of a PR, so cancel all previous instances.
+# Allow running master builds to complete to help with ccache refreshes.
 concurrency:
   group: general-build-${{ github.event.pull_request.number || github.ref_name }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 # Overall strategy for what sorts of builds to include:
 # We want a build for the newest and oldest supported version of each compiler.