Cobra, I had one female do this for me this year. It's a first for me. I've read that other breeders have it happen regularly. I guess it depends upon the snake. The girl that did the pre ovulation shed for me I think was because it's her first time. Not sure. Just a guess. But the answer to your question is, Yes, some do.
If you happen to notice ovulation, which is generally pretty hard because it only lasts about 24 hours give or take. But, if you notice, the snake should shed about 10-20 days after that, once that shed is complete it'll be roughly 30 days until she lays eggs.
If your male is not interested in her anymore then she is probably going to become gravid or already is gravid. When the female is about to ovulate or has ovulated, she will stop producing phermones, so the males will lose interest. It's a good sign of her being gravid, or about to be anyway. Also the lack of appetite is a good sign too.
Good luck, best wishes to you.