In Registry Finder with abbreviations active, I tried to delete 17 items. For each, I got a "could be dangerous, are you sure" type pop-up message from jv16pt. The lines dropped from the list. There were no system error messages in the bottom message panel. The backup went to the Other Backups area, but contained only header type information. The keys were still in the registry.
After turning off abbreviations and repeating the actions, the keys were deleted with no messages. A proper backup went to the Registry Backups area.
The root cause is certainly the same as this issue: https://www.macecraft.com/forum/viewtopic.php?f=41&t=5651
