Flycast Atomiswave Metal Slug 6 Sprites Corrupt

I have tried a bunch of different settings and none seem to help all the characters seemed to be surrounded by colored boxes. I have combed the internet and forums and tried various settings, different roms and cannot seem to make it go away unless I enable RTT (render to texture). This makes the issue disappear but I am not fond of the look it achieves (kinda smudgy). I settled on Gl for the driver (no difference with others, except for the ones that didn’t work.) I tried all the In Game Option settings, sometimes it would disappear for a screen or so but return. Everything has been updated through the Online Updater as of yesterday. Anyone have any ideas. Oh my Graphics card is a NVIDIA GTX 480, not sure if it is the culprit as I tried a bunch of other games and have not experienced this issue. Thanks in advance.