My colleague and I have recently been repeatedly encountering this glitch while trying to edit multiple choice questions in a survey. This is after the question was originally created, we go back to add or edit a choice and every time you click one of the response options, it pops up the edit box (as shown in the screenshot) and it won't go away. So if you click on one and then another, you end up with two -- and on and on, as shown with four at once in the image. It also doesn't actually accept any changes you make if you edit in the box.
This occurs for me (survey owner) and an external collaborator, and in multiple browsers (Chrome, Firefox, even Edge). I also tried a ctrl-f5 in Chrome. We were able to work around it by copying a multiple choice question from elsewhere in the survey and editing that one instead, but wanted to let you know because it's a pretty big pain.