So this is what we know for now:
-All modpacks (including custom ones), when ingame, are upsidedown AND mirrored.
-Problem only affects Mac OS users.
-Problem starts with an update question (even when there is no update avaiable). Saying YES or NO is the same result.
-That pack starts downloading the NATIVES file for no reason.
-Problem works both in new AND old launcher (so that let us know its not a local problem).
-Only the GUI (graphical user interface) is flipped over. The positions of where the buttons should be works for the mouse.
-Buttons are still in the same side (it should be on opossite side since its upsidedown).
-Only temporary sollution is to play in fullscreen (fn+f11). Bad if your keys normally stuck each 5 min (like me).
So... anyone have any idea? i dont have any.