diff --git a/.github/workflows/dotnet-workflow-common.yml b/.github/workflows/dotnet-workflow-common.yml
index af641907..5937761e 100644
--- a/.github/workflows/dotnet-workflow-common.yml
+++ b/.github/workflows/dotnet-workflow-common.yml
@@ -12,7 +12,7 @@ on:
       DOTNET_IMAGE_ENV_VARIABLES:
         required: false
         type: string
-        default: ''
+        default: {}
       CONTAINER_CI_LABELS:
         required: true
         type: string