diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 505c534b..a05de80c 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -55,7 +55,7 @@ jobs:
             # if this is a main branch build, just tag it with the flavor (eg. main and sandbox)
             type=raw,value=${{ matrix.flavor }},enable=${{  github.ref_name == 'main' }}
             # if this is a (non main) branch build, tag it with the flavor and branch name (eg. main-branch and sandbox-branch)
-            type=ref,event=branch,prefix=${{ matrix.flavor }}-,enable=${{ matrix.flavor != 'main' }}
+            type=ref,event=branch,prefix=${{ matrix.flavor }}-,enable=${{ github.ref_name != 'main' }}
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action