I was lying prone and firing the "Amphibia S" .22 pistol and the following pop-up message appeared.
"Confirmation of Changes
No entry
'bin\config.bin/CfgRecoils.recoil_prone'.
Continue"
Subsequent re-chambering and firing did NOT yield the pop-up message. However, I suspect if I shut down the client entirely and tried to reproduce, it would happen again.
Upon restart of client, lying prone, and again firing the Amphibia S, the pop-up re-occurred on the first shot (but not on subsequent shots).
This seems to be reproducible every time now on the first prone shot with the Amphibia S after restarting the client.
*Note: This is when looking down sites
**Note: Client does not crash or exit. Just a pop-up.
***Note: Also attempted to reproduce by restarting client, lying prone, and firing a P1 with an improvised suppressor. It did not reproduce. Then I tried the Amphibia S again and it did reproduce. It appears to be isolated to the Amphibia S.
[Update] - Apparently it does this the first time each session I fire the Amphibia S, regardless of being prone or standing.