Optima Red Top Battery Problem

Has anybody run into problems with Optima red top suddenly going dead or shorting out? Iam running dual battery setup witha red top for starting and a yellow top for audio. Both batteries are isolated from each other,except when the engine is running and both batteries charge from a dual 130 amp alternators. The yellow top is not presenting any problems even after an all session of wrenching and music. This is the third time of this happening. I'm ata loss for this.