"Run Exclusive" does not work after Jenkins restart/prepareForShutdown.

I prepared a "MAINTENANCE-BREAK"-job that asks for user input and made it a "Run Exclusive"-job in "Job priorities". I triggered the job, and saw that regular jobs( with default priority) were queued nicely. Then I rebooted the node which runs Jenkins Controller. We have configured Jenkins Controller to enter "prepare for shutdown"-mode when it starts, and it did. I noticed that the regular jobs were still queued, and my "MAINTENANCE-BREAK"-build was still running and waiting for user input. I canceled the  "prepare for shutdown"-mode, and expected the regular jobs to stay in queue because the "MAINTENANCE-BREAK"-build was still running - however those regular jobs started running. Also, any new triggered jobs are not queued even though the "MAINTENANCE-BREAK"-build is still running.

( Background: I thought of using the plugin as a work around for: JENKINS-60434 , so I can gracefully take our CI-system down and wait for the pipelines to finish before doing that. )