What specific Opera version as shown at the URL opera://about?

Does it happen with a test standalone installation or different profile?

Are you using more than one monitor? If so, which monitor is Opera's window on?

i dont even know how to dupe it

So, that means it only happens sometimes when you press esc to take the video out of fullscreen mode and not all the time?

whenever i unfullscreen a video it unfullscreens my entire browser how do i fix this

To fix the issue where unfullscreening a video unfullscreens your entire browser, try updating your browser, disabling extensions, and clearing your cache and cookies. If the problem persists, test with another browser or reinstall your current one.

The directions to reproduce were like this:

Goto https://www.youtube.com/watch?v=tAGnKpE4NCI for example, put the video in theater and press F11 to put Opera's window in fullscreen mode. Then, click the fullscreen button on the video toolbar to put the video itself in fullscreen mode. Then, press esc to take the video out of fullscreen mode. Result: After the video comes out of fullscreen mode, Opera's window automatically comes out of fullscreen mode too.

I've tried in theater mode and regular mode. No difference. Still can't reproduce?

@raze-player, is that how you're able to reproduce the issue? Also, are you using regular Opera (Opera One) or Opera GX?