When I went to send some teamups to an alliance mate, I noticed that a bunch of my characters were “LOCKED” and I could not send them. THIS IS NOT BECUASE I HAD RECENTLY SENT THEM. Many are characters I have never sent to anyone, ever. Did I miss an announcement about this? What’s the purpose of preventing you sending teamups? I don’t get it…
Sometimes if they’ve been ‘downed’ you can’t send them, maybe it’s that!
Passive powers; bugged powers; powers that won’t work as a team up.
Ah! Ok, that makes sense. Maybe they should, you know, change the team up powers to not being passive, and fix the bugs? I know, I know, that’s crazy talk! 
You know what probably makes the devs the happiest people on earth? Forum members using sarcasm to imply that the devs don’t do their job. It’s not funny. It’s not cute. It’s not absolved with a winky smily face. You’re being an ungrateful tinykitty and single-handedly making the forums a worse place. Congrats.
You may have missed this announcement about team ups becoming unavailable:
https://forums.505go.com/discussion/70298/r145-hot-fixes-updated-2-5-18#latest
And you know, among all possible bugs, a few team ups not working is probably pretty low impact. Note that the Team ups in this case are not bugged but have passive components that don’t operate when the character is not present on your team.
Huh?? What the what!?