Female mice are known to be particular when a new male is introduced. This is generally a territorial issue, so introducing both to a new territory at the same time will reduce the liklihood of that happening.

Alternatively, since you've got her seperated, clean both tanks, wait a few days, clean the one with the 1.2 again, and put her in with them. If you still have aggression issues then maybe she might just be a mean one...