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 created by the low priority job can prevent the high priority job from resuming. This can be avoided by configuring preemptive queues.