Screen glitch ONLY at end boss fight in The Underrot

Before I wanted to post this Topic issue, I asked around to some people in WoW Shadowlands and no one had a similar issue. I checked my graphics driver and it said it was up to date. But I find it strange how this only occurs at the end boss fight in the Underrot. When the fight starts, my screen begins to flicker and glitch out to the point where I can’t see my spellbar at all or any other of my bars, which means I can’t fight the boss properly. At the end of the boss fight when I try to find my portrait on the top left, it isn’t there either. Nothing shows up on my screen besides my character and the surroundings of the world. So, I can’t leave party, or leave the game by hitting “esc” at all. It doesn’t work. I have to press my windows key and right click the game to close it out. After that, when I log back on, it seems to work. However, if I were to try the dungeon again at all, the same exact glitch would happen at the end fight. And it’s only the end fight that this stuff happens. I don’t think its a graphic issue but it could be. Does anyone know how I can fix this? I’m, at this point, desperate.

No technical info, no way to help.

Post a dxdiag.

Directions in the stickies.

Stickies? I don’t understand

The blue posts at the top are stickied to be stay at the top. Standard internet nomenclature.