So this is not a bug but a logic and playability issue. First let me start off by saying I understand that there could be an overpowered part of this if changed but it would come at a sacrifice.
Ok so here’s the situation, a haven was getting attacked. The danger was extreme. I happened to have two ships nearby. So I sent them both. One had 7 soldiers and one had 6. One had a vehicle inside taking 3 spots, which is dumb on its’ own. Anyway, I went to deploy and it would only let me select 8 of the 13. So I did and got my butt handed to me by a queen. No way to win that level with what I had. Which is fine. But, I strategized how to win and my complaint is that the game would not let me execute my plan. Please make an adjustment.
Well, there is always the possibility to go and vote for the feature here: https://phoenixpoint.canny.io/feedback/p/dont-limit-squad-size
Of course UnstableVoltage said that the number of votes doesn’t really count, but I’m not sure to what extent.
Out of curiosity, what was your squad make-up?!? A full squad of 8 should be able to win this unless they’re very under-leveled. Even if the majority were level 5-6. or perhaps equipment available could also make-or-break the issue.