Similar to MC-229 but that says it was fixed. This happens in 1.21.4 and probably all the way back to when F11 became a thing to toggle fullscreen.
Steps to Reproduce:
Open video settings
Scroll to the Fullscreen option
Keep it on or off, doesnt matter
Press F11
The fullscreen option will say the reverse of if its in fullscreen or not
If you reopen the video settings, it will fix itself
In some older versions, eg. 1.16.5, you have to turn fullscreen off at the same time you turn it on with F11 and sometimes it will do it. Also why cant i add that to affected versions list? Can a mod add like 1.16.5 but like as partly affected?
I am able to reproduce the reported behavior. It was introduced in 24w09a. Contrary to the assumption in this ticket’s description, MC-229 had indeed been fixed (in 14w29a) and differs in that, back then, the Fullscreen button did not update its value when the Video Settings menu was reopened.