When changing the target branch to a PullRequest the rerun of the Pipeline is skipped with

No changes detected: PR-5 (still at …)

because changes to the target branch seem to not be taken into account at all (see also JENKINS-68759).

• The new (default) check target name will never get pushed
• No update when merge result changes

Any change to the triplet

• target-branch-name
• target-commit (in case merged state is also checked)
• source-commit

MUST trigger a new unique execution!