Tonight I used the DEL Key with catastrophic results
I knew that Deleting was bug-ridden but in this case I watched through and realised what is happening.
I flagged 5 Images as 'Reject' and selected them.
I clicked on the first one and pressed DEL.
Instead of that one being deleted, it was the next one, which I found in the recycle-bin with its .xmp and a .nocache entry.
Pressing Ctrl+Z "Undo Remove version" restored it correctly.
If I had not noticed, I would have lost my Raw Image Masters
I have reported it to the Survery Monkey and I hope others will do the same.
EDIT: Also noted the INS Key Bug