My thank you

[Trainbother]

I've been having a bit of bantery back and forth with a man. When I give him a slightly sarcastic compliment he'll sometimes respond "my thank you". (OK, twice).

The first time I assumed it was a typo/ autocorrect and he meant "why, thank you", which I think is a fairly common phrase. Or do I have it wrong?

"my thank you". (OK, twice).

I don’t understand this. If I type ok twice it doesn’t correct to my thank you.

I've heard of "Why, thank you" - could it be that?