No, it's not normal for that to happen after they have tied.
Yes, it is an extremely bad idea for you to leave them to tie unsupervised and very dangerous to both your male and female. It is very likely that your male suffered injury as a result, given your description of what you observed.
Just to add, since you are clearly very uneducated on the breeding process in general, as evident by your comments, you probably shouldn't be breeding them in the first place. These are issue you learn how to handle IN ADVANCE, not something you pick up and learn as you go.