There is a snapshot, even though it does not show up in the Snapshot Manager for whatever reason.
469765380 6144 -rw------- 1 root root 5636608 Feb 19 18:23 AIBS2019_1-000001-ctk.vmdk
461376772 349503488 -rw------- 1 root root 446743482368 Feb 19 19:20 AIBS2019_1-000001-sesparse.vmdk
465571076 0 -rw------- 1 root root 388 Feb 19 18:23 AIBS2019_1-000001.vmdk
452988164 6144 -rw------- 1 root root 5636608 Feb 19 11:05 AIBS2019_1-ctk.vmdk
171966468 23085449216 -rw------- 1 root root 23639499997184 Feb 19 11:30 AIBS2019_1-flat.vmdk
176160772 0 -rw------- 1 root root 572 Feb 19 06:01 AIBS2019_1.vmdk
The second line shows the snapshot, and the last line the date/time when the snapshot has (most likely) been created.
The usual way to get rid of such a snapshot would be to create another snapshot, and then click "Delete All" in the Snaphot Manager.
However, with no free disk space this may not work.
Do you see an option "Consolidate" in the VM's context menu?
André