But Spock's act is still open to interpretation, because Kirk never mentions Rayna again. It's also unclear what if anything was reported to Star Fleet Command about Flint and Rayna.
He never mentions Edith Keeler or Miramanee or Lenore Karidian or Ariel Shaw or any of his other love interests again, either. I think we can assume that Spock didn't erase all those memories as well . . . .
Episodic TV shows of that era had short memories, especially where guest-stars were concerned.