That's weird, can you open the browser console (press F12 -> click Console tab) and see if there are any error messages when the bug happens?
little update on the bug issue, it seems to only be the visual bug stays around, I haven't had any issues with the combat screens any longer. It could still be an issue but like a start of game issue, now that I'm later in the game the issue has dissolved completely speaking about the combat screen bug btw.