It happens to me, always, on PC and iPad. The only way I can get rid of the unwanted quote box is going through some steps (a bit annoying, but easy enough to do) 1 - I have to click inside the quote box and 'erase' a little of the text; even just a few letters will do. And if it's just the empty quote box, you still have to click inside it and then hit the backspace key a few times.  2 - then on the top of the quote box, click at the end of the poster's name and backspace a few times,