Mentioned this issue in the Discord chat last night but now I actually know how to replicate it.
Opening chat, changing the tab and then pressing ESC right after to close the chat opens the menu. When closing the menu the mouse remains unlocked as if the chat or any other UI is still opened and you can’t click in to control the game anymore. It fixes itself only after a reload. You can still open chat, inventory, tab etc. but you can’t control yourself.
In condo: (it doesn’t let you move or control the camera)
Also affects game worlds (you can move around but can’t control the camera)