diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9dca7f413a46095d49b78ba38b44199126a9ae10..f49c7d49f7238b76d67039c63b4d50fc6a3141e6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: <text>Copyright 2023 Arm Limited and/or its
+# SPDX-FileCopyrightText: <text>Copyright 2023-2024 Arm Limited and/or its
 # affiliates <open-source-office@arm.com></text>
 #
 # SPDX-License-Identifier: MIT
@@ -39,15 +39,17 @@ trigger-meta-cassini:
     variables: false
   stage: Build
   rules:
-    - if: $META_CASSINI_PROJECT == ""
+    - if: '$META_CASSINI_PROJECT == "" ||
+           $META_CASSINI_PROJECT == null'
       when: never
-    - if: '$CI_MERGE_REQUEST_IID == "push"'
+    - if: '$CI_MERGE_REQUEST_IID'
       variables:
         META_CASSINI_TARGET_BRANCH: "${CI_MERGE_REQUEST_TARGET_BRANCH_NAME}-dev"
     - if: '$PARENT_PIPELINE_SOURCE == "schedule"'
       variables:
         META_CASSINI_TARGET_BRANCH: "${CI_COMMIT_BRANCH}-dev"
-    - if: $META_CASSINI_TARGET_BRANCH == ""
+    - if: '$META_CASSINI_TARGET_BRANCH == "" ||
+           $META_CASSINI_TARGET_BRANCH == null'
       when: never
     - !reference [".build-image:rules:k3s", rules]
     - !reference [".build-image:rules:k3s-dev", rules]