I have a co worker in a another department who I'm friendly with. Without being too outing, my role is similar to a behavioural youth worker. My colleague does something completely different and has never seen me 'at work' with the youths. She sees me when I'm on my lunch break.
Today, she asked me about a particular youth who can be quite difficult that she has seen around the building. I said that I've had to be quite firm with them. My colleague said in an slightly mocking/jokey voice that she doesn't see me as someone who can be firm. She repeated this twice saying 'you just don't look like it'. I didn't pay much attention to it then but when I mentioned it to my department colleagues, they said 'that's a bit rude. You're definitely firm and fair on the kids'. I've also noticed that when I've ever mentioned something successful that has happened for me, she will do a surprised look of 'really??'.
Should I just stop talking to her as we don't cross professionally anyway? We're just c friendly and she'll come over and ask if I want to grab a coffee together.