diff --git a/.github/workflows/build-web.yml b/.github/workflows/build-web.yml
index ba4f2599f37..7e89a5c7cd7 100644
--- a/.github/workflows/build-web.yml
+++ b/.github/workflows/build-web.yml
@@ -216,7 +216,7 @@ jobs:
       - name: Generate Docker image tag
         id: tag
         run: |
-          if [[ $(grep "pull" <<< "${GITHUB_REF}") ]]; then
+          if [[ "${GITHUB_EVENT_NAME}" == "pull_request_target" ]]; then
             IMAGE_TAG=$(echo "${GITHUB_HEAD_REF}" | sed "s#/#-#g")
           else
             IMAGE_TAG=$(echo "${GITHUB_REF_NAME}" | sed "s#/#-#g")