diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1dafef2b75a..1d6e5083305 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -7,7 +7,6 @@ on:
       - "**"
   pull_request:
     types:
-      - closed
       - opened
       - synchronize
       - reopened
diff --git a/diff-sha.sh b/diff-sha.sh
index f825c0465ae..efe250978f0 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -194,12 +194,10 @@ else
 
   if [[ -z $INPUT_BASE_SHA ]]; then
     if [[ "$INPUT_SINCE_LAST_REMOTE_COMMIT" == "true" ]]; then
-      echo "::debug::Fetching remote current branch..."
-
       PREVIOUS_SHA=$GITHUB_EVENT_BEFORE
-      
+
       if ! git rev-parse --quiet --verify "$PREVIOUS_SHA^{commit}" 1>/dev/null 2>&1; then
-        PREVIOUS_SHA=$(git rev-parse origin/"$CURRENT_BRANCH")
+        PREVIOUS_SHA=$GITHUB_EVENT_PULL_REQUEST_BASE_SHA
       fi
     else
       echo "::debug::Fetching remote target branch..."