Refer to pull request 152 for an initial idea that might prevent the build storm.
It seems that line 2082 in the diff might not be handling the initial startup case where a job already exists but the lastSeenRevision file has not been written.
Mark Waite Since you were able to repro this do you have an instance where you can try this incremental? https://repo.jenkins-ci.org/incrementals/org/jenkins-ci/plugins/branch-api/2.5.1-rc752.20712eff7952/
If trying to repro this on an existing instance that was upgraded, you will of course need to downgrade and then delete the lastSeen files first.
That incremental build resolved the issue. Thanks!