Is it weird for a past fling to do this?

My past fling and I work together (unexpectedly). He ended it because of thoughts for another girl and it was really messy. We work food and he was in the front and I was in the back on a different register. He pointed out that I was doing a certain behavior “the whole time” and said I “must be talking to somebody”. Since we were talking about me considering getting back with my ex. He claims the only reason he realized it is because he’s just observant and isn’t interested like that anymore. But I think it’s… weird? Idk