My friend started stuttering in front of me.

My friend started stuttering in front of me. I’ve recently started hanging out with a co worker outside of work and I noticed they started stuttering. The only reason I noticed it is because I have a stutter and when they first did it I genuinely thought they were mocking me. We have been working together for about 6 months and I had never heard them stutter before. I frequently stutter but it does get severe if I’m really anxious, which I was when we first decided to hang out outside of work. Suddenly while we were hanging out and now every time Ive seen them after they have developed an extremely severe stutter, not being able to get through a sentence complete with a weird eye twitch when they are trying to get through words. I just feel like they’re mocking me or something? Idk just strange.