Honestly, same - I totally feel you! When I first stanned Iz*One, I didn't even know temp groups existed. I found out the hard way when I saw a thread (not on here) talking about their inevitable disbandment. I was like, "Whoa, wait a minute - I just became a stan and they're already DISBANDING?" and another user was like, "Yeah, they're a Produce group - Produce groups are temporary."
And then when I decided to stan Kep1er, I was watching a video of theirs, and some of the comments were like, "I'll miss them when they disband" and whatnot. I asked one of them if they were temps, and they said yes.
Why do I do this to myself??? I just jump right in without seeing if they're temp or not, only to have my heart broken when I find out they are.