This is a side effect of issue #7753.
After Velero server restarts, the running maintenance job goes orphan because of #7753.
When Velero server runs a new maintenance job, it checks if there are running maintenance jobs, if so, it aborts creating a new job.
As a result, after Velero server restarts, no new maintenance job could be started until all the orphaned & running maintenance jobs complete
This is a side effect of issue #7753. After Velero server restarts, the running maintenance job goes orphan because of #7753. When Velero server runs a new maintenance job, it checks if there are running maintenance jobs, if so, it aborts creating a new job. As a result, after Velero server restarts, no new maintenance job could be started until all the orphaned & running maintenance jobs complete