I honestly couldn’t tell you what I did for this to happen. I was bug testing and stuff and I noticed this. It doesn’t break the game or anything, but, it’s obviously a problem. It’s only visual.
There’s barely anything we can know from a screenshot, unless someone happened to run into a similar problem before. As a guess, make sure you didn’t accidentally disable layers in your emulator.
If you want someone to look into this problem, you need to give more information, preferably through a report7z in FE_Builder_GBA -- If you have any questions, attach report7z or the FEBuilder channel in FEU’s Discord channel.