I’m not quite sure why you’re trying to run both a 64-bit and a 32-bit version of the same plugin, specially at the same time. There may be be funky bad interactions going on there, for example, both of them trying to access hardware that may be locked and so forth. Also, once you start using a wrapper to make 32-bit plugins work, you now have multiple points of failure where jBridge may not be handling the 32-bit plugin properly which may cause the wrapped plugin to be broken from Gig Performer’s perspective.
Generally, if you’re using a wrapper to try and make 32-bit plugins run in a 64-bit environment, all bets are off. Some may work, some won’t, some will be intermittent.
I do know that many users have worked with Midi Guitar 2 (64-bit version) in Gig Performer with no problems.
The jBridge people do know about Gig Performer so if you can in fact narrow down the problem to a 32-bit plugin, you should reach out to them.