This shouldn’t happen. I would recommend checking in with your vet. Sometimes, but rarely, after spays, pieces of the reproductive tract are left inside the cat, which can cause them to go back into heat.
There might be other possible causes, too, that I’m not aware of (I’m not a vet), so that’s why I would definitely advise you to make an appointment with your vet, to get her fully checked over.
Thanks. She's calling, rubbing, and rolling on the floor like she did prior to spay. She's in no pain, still plays, eats, etc... as normally otherwise.
There was a recent thread on TCS about this problem. After the owner learned of the possibility of remaining reproductive tissue from the thread, they took the cat back to the vet.There was remaining tissue. Vet removed it, problem solved.
Hopefully, a moderator might be able to recover the thread for you.
It may be that part of her ovaries or uterus is left over and is causing her to go into heat. Take her to the vet... They should be able to fix it with another surgery.
Here are links to two threads. The first one is oldish, but there is a reference to a vet being able to give an injection to help highlight the remaining ovarian tissue
Hmm. I learned something today. Didn't know this was possible. Both mine are spayed and neutered and fortunately have not displayed any of those things you mentioned.