By the way, is it possible that it is because the females were big enough but not mature enough? I know snakes are often bred at 2 years, but sometimes they don't "go". Could that be a reason they were refusing the male after a few locks?
Or that they had really small penes and thus everyone thought they were females? We probed both sides by the way just in case they were missing a pene. and they both were "female" on both sides.