It happens with all games/apps which want 65k colors. That diskmag as an example, but the same issues happen in games 11th hour, TombRaider, Screamer2, Earth2140, etc.
Want to know if you have the same on morphos or not, because if yes, then it probably DOSBox endian issue, and if not, then it our SDL. The issue happens with both dynamic and normal core, so not related to jit.