I've noticed that AMP won't prompt for a password when adding new workshop items. To reproduce this issue, create a fresh Arma 3 instance and add workshop items. After updating the server, restart the whole instance and add another workshop item. AMP is trying to login to steam using "anonymous" and won't prompt for login details. I also see no option to use the account I've purchased the game with.
The error output in console is "Warning: failed to init SDL thread priority manager: SDL not found"