If you bought your GP32 recently, it could be one of the ones dubbed BLU+ with the new LCD screen which causes some display issues. I don't have oe of these, so don't know much about it, but it is well discussed on here so I'm sure someone can verify if this is the case, especially if you only notice it in certain programs. Which Genesis emulator are you using? I don't think the SNES one works with the BLU+ yet, but DrMD does.
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