Strange boxes appearing behind text after export

Using version 17.04.02 on Windows 8.1. Strange boxes appear behind all text only on the exported video. The filter seems normal. The boxes are also thick white rectangles even if the font of the text is different.

http://imgur.com/a/jjGpi

It is trying to say INVALID, but it had a problem to do so due to a bug. Whatever file is used for the background behind the text is not working.