Why does my girlfriend bring up another guy a lot?

TL;DR My girlfriend brings up another guy in her class that is super funny and all that, seemingly randomly, I am jealous, should I talk to her about this?

Hey there, my gf (21F) and I (22M) have been dating for 9 months now, it is serious and we talk about a future together, details of a house we would want and stuff like that. It is awesome and we love each other very much, but recently she started bringing up this guy in her class that is, "so funny,". We would be hanging out and she would mention something funny this guy said in class, and it has nothing to do with what we are doing most of the time, it is simply because she wants to tell me that story. I don't know why she brings him up so much and she showed me a text that was not even a joke and she thought it was funny. I joke around with her in a similar way but it seems like she has a better time with this dude in her class from the way she reacts.

I feel jealous honestly and want to talk to her about it.

Why does she bring him up a handful of times on different occasions for this past week or so? They also send each other Instagram reels and stuff. We do that too, but it is just another salt to the wound.

Her actions don't line up with her words, I think is common sense not to mention how great you think members of the opp sex are when you are around your SO. I talk and have fun with girls in my class, no biggie, she can have guy friends too, I am close with some of them, but why mention this dude? I never mention the girls I talk with unless it has to do with the conversation.

Should I confront her on this? If roles were reversed, I think it would be wrong too.