I've now had this happen twice (possibly more); when doing a streak with 4 Aeronauts in my gang I will suddenly have less. First time it went from 4 to 1 with an extra Heavy Gunner and one empty space instead. Tonight it only went down by 1 and I received two extra Gunners instead. I believe this has happened before but I just assumed it was my mistake.
How bizarre! Can you submit an in-game support ticket with the details (preferably including the names of your opponents during the streak) so that we can take a look? It's not something we've had reported before, and I streak on a regular basis with Aeronauts and haven't seen it myself (I go with six though).
ok I will try, but as it's only noticeable on the next attack which can be several minutes later and multiple swipes to the next base it may be tricky!
Dont worry about this anymore it's not happened again from what I've seen, and I've retired from the game now.