It's cold, because you're going to part ways soon.

Maybe there is a competitive interest relationship between them.

It's hard to avoid being a little distant

Relax.

Life is like this. Only parents will be kind to you and think of you without reservation. Everyone else has their own goals.

Therefore, you should adjust your mentality in time. There are many such situations in society, and you must adapt to the interpersonal relationship at work.