Similar topic, but slightly different situation. I remember one time the SD addressed me as "Doctor" and asked me if I could assist with a medical issue if one were to arise during flight! My surname was pronounced correctly, so unless a passenger next to or near me had the same name, he was talking to the correct person (but not profession!).

I immediately corrected the SD and told him I was nothing of that sort. I later checked my account and it still showed me as "Mr.", so perhaps I may have mistakenly changed it during that booking process. I'm not sure which airlines shows honorifics on BPs, but AC doesn't, and I was flying them. It was a weird one-off. My booking also showed Mr.