I wouldn't stress too much. I had about the same thing happen to me. I have 2 female het pieds, and 1 male het, I thought I put the female in with her sister while I was cleaning her tub, but it was the male. It was only about 30 minutes when I opened the tub to put her back in her own tub, and they were locked, both the male and the female were only 300ish grams. There's no way the female would be ready to breed so I didn't worry too much, but I made sure not to make that mistake again! Males will lock with each other, so it's not like they only lock with females that are ready to breed, they lock with anything.