Vanishing Team-Ups

chamber44
chamber44 Posts: 324 Mover and Shaker
This *might* be an issue, or I might not be paying attention.  

But - i don't often use my team-ups, and yet i've noticed that I suddenly only have 1? I feel like it was just a few days ago that I got the message that "You would have earned a team-up but your slots are full yada yada ..." 

Am I just going crazy, or does this happen somehow?