I suspect that this might have come with
Webmin 2.300 and Usermin 2.200 released (February 14, 2025).
At least something was changed in that module (and the permissions list is now sorted differently than before):
“Fix to improve how permissions are displayed in MySQL/MariaDB module.”
As I said, at the end of January with Webmin 2.202, I didn’t have these issues yet…