@Darksoft, I believe I found a bug with Shock Troopers (set 2) which is reproducible for me on an MV1C with UniBIOS 4.0, even after a backup RAM reset.
1) The first time loading the game I first enabled the violence soft dip setting and game worked fine. Attached is a screenshot of the soft dip settings where Violence = on and Language = English
2) The next time I attempt to play the game I get an Exception Error Handling message (see screenshot)
3) If I press C to reboot, then press the B+C+D hotkey to enter the operator menu and enter the soft dip setting Language is now set to Japanese (see screenshot). If I change it to English and exit out the game works fine.
4) The game will continue to work between power offs until I remove it from a slot and re-program it. At which time the same thing will happen. It will get an error message and entering the soft dip menu the language will have reverted to Japanese. As before changing back to English fixes the game so it's playable.
I've also noticed a few times after playing Shock Troopers for a while and then switching to the game in Slot 3 it has no sound. Slot 2 will still have sound and even after toggling back and forth between slots #3 will always be silent. If I exit back to the menu and immediately re-load the games sound is restored on slot 3. Perhaps this isn't related to Shock Troopers (set 2) at all, but it's the only game I've experienced it with. In both cases there was a different game in Slot 3 (Magician Lord and then Cyber Lip) that lost sound.