diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 35d7096e8483b7fa2bbbdf44097f1243396cabee..e561bf4083cd8b710b09f678910dc27f4f32db30 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -63,8 +63,8 @@ workflow:
     - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
     - if: '$CI_PIPELINE_SOURCE == "web"'
     - if: '$CI_COMMIT_BRANCH == "master"'
-    - if: '$CI_COMMIT_BRANCH =~ /^v[0-9]+\.[0-9]+-(alpha|beta|stable)/'          ## main stable branch: vX.Y-stable
-    - if: '$CI_COMMIT_BRANCH =~ /^v[0-9]+\.[0-9]+-[a-z]+-(alpha|beta|stable)/'   ## special stable branch: vX.Y-acadia-stable (etc)
+    - if: '$CI_COMMIT_BRANCH =~ /^v[0-9]+\.[0-9]+-\(alpha\|beta\|stable\)/'          ## main stable branch: vX.Y-stable
+    - if: '$CI_COMMIT_BRANCH =~ /^v[0-9]+\.[0-9]+-[a-z]+-\(alpha\|beta\|stable\)/'   ## special stable branch: vX.Y-acadia-stable (etc)
     - if: '$CI_COMMIT_TAG =~ /^v[0-9]+\.[0-9]+\.[0-9]+/'            ## commit tags start with vX.Y.Z with optional suffix
 
 ## plan: