diff --git a/.github/workflows/1_on_pull_request.yml b/.github/workflows/1_on_pull_request.yml
index 38d713b1..efecba2f 100644
--- a/.github/workflows/1_on_pull_request.yml
+++ b/.github/workflows/1_on_pull_request.yml
@@ -791,7 +791,7 @@ jobs:
         GPML_FILE="${{ needs.get-gpml.outputs.gpml-file }}"
 
         # Fetch the diff for the GPML file in the current PR
-        diff_output=$(gh pr diff "$PR_NUMBER")
+        diff_output=$(git-diff "$PR_NUMBER" -- "$GPML_FILE")
         echo "$diff_output"
         echo "diff_output=$diff_output" >> $GITHUB_ENV