no worries Alan, and thank you. Your issue is the same issue I'm having.
The one's I need look like this the one in the attachment
I was hoping someone came up with a DIY. I'm not overly impressed with the durability/fuctionality of the OEM mounts.
I read, as you must have, when you over-tighten, you disform the plastic. However I have a few that aren't deformed, and as tight as they should be but spin fairly easily when "bumped" slightly.
This may be because they were not correctly tightened by the previous owner.
I did find replacement on flea-bay for just under $14 which isn't too bad
https://www.ebay.com/itm/Alesis-Anti-Spin-Rotation-Stopper-for-DMPad-Cymbal/201389180674I just wanted to see if there was a DIY option someone had come up with.