diff --git a/action.yml b/action.yml
index 627ee74..f9c8e2f 100644
--- a/action.yml
+++ b/action.yml
@@ -27,7 +27,7 @@ inputs:
   SHA:
     description: 'The SHA of the latest commit (automatically set)'
     required: false
-    default: ${{ github.sha }}
+    default: '${{ github.sha }}'
   TOKEN:
     description: 'The GitHub access token to allow us to retrieve, create and update issues (automatically set)'
     required: false