In S3 few characters return to the time when S1 started. To see their old selves having different haircuts
It's hilarious. I binged S3. And one guy returns to 2021, few weeks before events in E1S1 started. To see his friends. And those 3 men "in the past" had same longer hair that actors have by season 3.
I actually tuned in S1E1 to check. And yep - Gavin, Scott and Sam had very much shorter hair. It was funny how producers didn't even try to make it look believable and to put wigs or hats on them. They were like: "Whatever, we don't time for this' and let actors have that long hair they grew for few years that show is on.