While everything initially seemed to work fine when running JA3, I quickly noticed an issue where certain buttons couldn't be clicked, and in lists, the item above the one I selected would be highlighted instead.
Shortly, I noticed that when playing in fullscreen mode, a light grey bar appears at the top of the screen, causing the mouse coordinates to be misaligned vertically. As a result, I each time had to click slightly below the intended button to activate it.
Fortunately, I found a workaround: switching the game to windowed mode and then back to fullscreen after startup removes the grey bar and restores proper mouse functionality.
Although it's a bit inconvenient to perform this fix each time I launch the game, it allows me to play without any further issues once it's done.
--
This happens on a Mac Studio M2 Ultra … not sure if it applies to all setups or not.