Did you tried it once or it happen all the time ?
If you haven't retried it could be a bug, there sometime some bug in rpg maker game when skipping text to quickly during some scene (especially when there character moving / picture - tint... being use).
If it happen all the time, even when having the scene play at normal speed, the most probable answer is a problem with the coding of the scene, like a missing line to remove the back screen superposed on the normal playing screen.
If that's the case, the only option is to correct the coding in the game...