diff --git a/.github/workflows/ci-suite.yml b/.github/workflows/ci-suite.yml
index 15c75bb15d..c316b5b649 100644
--- a/.github/workflows/ci-suite.yml
+++ b/.github/workflows/ci-suite.yml
@@ -203,7 +203,7 @@ jobs:
 
     - name: Set TGS4_GITHUB_REF for PR
       if: ${{ github.event_name == 'pull_request' }}
-      run: echo "TGS4_GITHUB_REF=${{ github.event.base_ref }}" >> $env:GITHUB_ENV
+      run: echo "TGS4_GITHUB_REF=${{ github.base_ref }}" >> $env:GITHUB_ENV
 
     - name: Set TGS4_GITHUB_REF for push
       if: ${{ github.event_name == 'push' }}