diff --git a/.github/workflows/upstream pretest.yaml b/.github/workflows/upstream pretest.yaml
index 1a1e09fb..04b4efb7 100644
--- a/.github/workflows/upstream pretest.yaml	
+++ b/.github/workflows/upstream pretest.yaml	
@@ -135,10 +135,10 @@ jobs:
                         if ($pr_num -in $submodule_by_repo[$repo].pretest_sha_by_pr.Keys) {
                             
                             $core_pretest_branch = "subm-pretest/$repo/$pr_num"
-                            $core_fetch_specs += "refs/heads/$core_pretest_branch:$core_pretest_branch"
+                            $core_fetch_specs += "refs/heads/${core_pretest_branch}:${core_pretest_branch}"
                             
                             $fork_pretest_branch = "pretest/$pr_num"
-                            $subm_fetch_specs[$repo] += @("refs/heads/$fork_pretest_branch:$fork_pretest_branch")
+                            $subm_fetch_specs[$repo] += @("refs/heads/${fork_pretest_branch}:${fork_pretest_branch}")
                             
                         } else {
                             Write-Host "--- MISSING FORK PRETEST"