diff --git a/.github/workflows/pull-request-commentor.yaml b/.github/workflows/pull-request-commentor.yaml
index 0e4c5888add..e1e3a56a445 100644
--- a/.github/workflows/pull-request-commentor.yaml
+++ b/.github/workflows/pull-request-commentor.yaml
@@ -21,19 +21,30 @@ jobs:
         branch: [release-v3.8, release-v3.9, devel]
         k8s: ["1.25", "1.26", "1.27", "1.28"]
         exclude:
+          # The exclude items below are dynamically constructed. If the
+          # base_ref matches the given branch, it will be excluded from the
+          # test matrix.
+
           # the next Ceph-CSI version will not be tested with old Kubernetes
           - k8s: "1.25"
-            branch: devel
+            branch: >
+              ${{ "devel" == github.base_ref
+              && github.base_ref || "no-exclude" }}
+
           # Ceph-CSI <= 3.9 was released before Kubernetes 1.28
           - k8s: "1.28"
-            branch: release-v3.8
+            branch: >
+              ${{ "release-v3.8" == github.base_ref
+              && github.base_ref || "no-exclude" }}
           - k8s: "1.28"
-            branch: release-v3.9
+            branch: >
+              ${{ "release-v3.9" == github.base_ref
+              && github.base_ref || "no-exclude" }}
 
+    # watch out, matrix.branch can not be used in this if-statement :-/
     if: >
       (github.event.label.name == 'ok-to-test' &&
-      github.event.pull_request.merged != true &&
-      github.base_ref == matrix.branch)
+      github.event.pull_request.merged != true)
 
     steps:
       - name: >