Discord Bug Graphic

Hello, I had a graphic bug:
I was opening multiple Discords of the installable version for PC (Windows 8.1) so I despaired that it did not load fast, so I went to the web page that loads faster, I was writing a message but I just loaded the installable version and copied my message from the page to the program and finish writing it, then I went to a friend's server and I was seeing the messages, and when I pass the Mouse over the messages they wrote, it turns black right where the Mouse passes, and when I try to go to arrive as the messages accumulate.