diff --git a/azure-pipelines/templates/ci-git-rebase.yml b/azure-pipelines/templates/ci-git-rebase.yml
--- a/azure-pipelines/templates/ci-git-rebase.yml
+++ b/azure-pipelines/templates/ci-git-rebase.yml
@@ -5,5 +5,6 @@ steps:
 - bash: |
     git config user.email 'info@openttd.org'
     git config user.name 'OpenTTD CI'
-    git rebase origin/$SYSTEM_PULLREQUEST_TARGETBRANCH
+    git rebase origin/${SYSTEM_PULLREQUEST_TARGETBRANCH}
   displayName: 'Rebase to $(System.PullRequest.TargetBranch)'
+  condition: and(succeeded(), eq(variables['Build.Reason'], 'PullRequest'))