diff --git a/src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubSCMSource.java b/src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubSCMSource.java
index b508fa0c6..6a2049d0a 100644
--- a/src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubSCMSource.java
+++ b/src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubSCMSource.java
@@ -1688,7 +1688,16 @@ protected SCMRevision retrieve(SCMHead head, TaskListener listener)
           }
           PullRequestSCMRevision prRev =
               createPullRequestSCMRevision(pr, prhead, listener, ghRepository);
-          prRev.validateMergeHash();
+          try {
+            prRev.validateMergeHash();
+          } catch (AbortException e) {
+            listener
+                .getLogger()
+                .format(
+                    "Resolved %s as unmergable pull request %d: %s.%n",
+                    prhead.getName(), prhead.getNumber(), prRev.getPullHash());
+            return null;
+          }
           return prRev;
         } else if (head instanceof GitHubTagSCMHead) {
           GitHubTagSCMHead tagHead = (GitHubTagSCMHead) head;