diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 43434f0b74..2af13b34da 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -81,10 +81,14 @@ jobs:
           BUILD_TAGS=()
           # Have tags for tracking builds during pull request
           SHA_SHORT="${GITHUB_SHA::7}"
-          COMMIT_TAGS+=("pr-${{ github.event.number }}-${MAJOR_VERSION}")
-          COMMIT_TAGS+=("${SHA_SHORT}-${MAJOR_VERSION}")
 
-          BUILD_TAGS=("${MAJOR_VERSION}" "${MAJOR_VERSION}-${TIMESTAMP}")
+          # Using clever bash string templating, https://stackoverflow.com/q/40771781
+          # don't make malformed tags if $MAJOR_VERSION is empty (base-image didn't include proper labels) --
+          COMMIT_TAGS+=("pr-${{ github.event.number }}${MAJOR_VERSION:+-$MAJOR_VERSION}")
+          COMMIT_TAGS+=("${SHA_SHORT}${MAJOR_VERSION:+-$MAJOR_VERSION}")
+
+          BUILD_TAGS=("${MAJOR_VERSION}" "${MAJOR_VERSION:+$MAJOR_VERSION-}${TIMESTAMP}")
+          # --
 
           BUILD_TAGS+=("${TIMESTAMP}")
           BUILD_TAGS+=("latest")