diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index d0518fa6879e2..8594e1e91ee99 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -149,7 +149,7 @@ jobs:
         uses: llvm/actions/install-ninja@main
       - name: Build and Test
         run: |
-          source <(git diff --name-only HEAD~2..HEAD | python3 .ci/compute_projects.py)
+          source <(git diff --name-only HEAD~1...HEAD | python3 .ci/compute_projects.py)
 
           if [[ "${projects_to_build}" == "" ]]; then
             echo "No projects to build"