lvm2 is caching state  active DM entries. However when there was a change of active DM devices from the moment  of 1st. scanning and grabbing the lock and before there was no active DM device - then the lvm2 was incorrectly decided to keep the cache.

As a result it could have left some DM devices in table while dropping lvm2 metadata for such devices.

To reach this case one could run in parallel this loop:

1st. terminal:

while true; do lvcreate -n lvol1 -l1 vg  || break; sleep 2; lvremove -y vg/lvol1  || break; done

2nd. terminal:

while true; do lvchange -ay vg/lvol1; sleep 1; lvchange -an vg/lvol1; sleep 1; done