[OpenGL] Graphical glitch in "Game Boy Advance Video - Pokemon" episodes

[RafaelTrepaUnCarballo]

There's a glitchy multi-color square in the upper left corner of the screen with the OpenGL render (Software render is unaffected).

The other GBA Video collections I tested aren't affected, apparently only the Pokemon videos. It's also noteworthy the OpenGL render goes a bit slow, even at native res, whereas the Software render runs full speed.