Arrays finish but don't leave queue

Apparently we sometimes get the situation where, on running

qstat -Jp

we can see that there are array jobs at 100% done, but remain in the queue.

This causes issues with the PBS cgroups hook not clearing.

We can - and do - manually remove the jobs from the queue, but were wondering if there was a fix for this?

We have PBSPro 19.1.1 on CentOS 7.6