A job can be suspended by its owner or the LSF administrator. These jobs are considered user-suspended and are displayed by bjobs as USUSP.
If a user suspends a high priority job from a non-preemptive queue, the load may become low enough for LSF to start a lower priority job in its place. The load that is created by the low priority job can prevent the high priority job from resuming. This can be avoided by configuring preemptive queues.