diff --git a/.github/workflows/netlify-deploy-preview.yml b/.github/workflows/netlify-deploy-preview.yml
index 72d00d3b69..ebeef0bbe9 100644
--- a/.github/workflows/netlify-deploy-preview.yml
+++ b/.github/workflows/netlify-deploy-preview.yml
@@ -40,7 +40,7 @@ jobs:
       - name: get changed sub-site
         id: get_changed_subsite
         run: |
-          CHANGED_DIRECTORY=$(git diff --name-only ${{ github.base_ref }}...${{ github.head_ref }} | grep -E 'sites/(main-site|docs)' | head -n1 | cut -d'/' -f2)
+          CHANGED_DIRECTORY=$(git diff --name-only ${{ github.base_ref }}...HEAD | grep -E 'sites/(main-site|docs)' | head -n1 | cut -d'/' -f2)
     outputs:
       changed_directory: ${{ env.CHANGED_DIRECTORY }}