I'm no expert as I had just started 2 days ago but I'd pay it forward as Ualaa and Lax have helped me quite a bit already.

I'd start checking keybinds in-game first. This happened to me, though with just 1 character to another. Found out that ctrl+F11 (which is the key passed to the character/window to follow a specific toon) is keybound. Ack! So when i cleared that, the character started following/assisting the other toon. Check isboxer's modifiers + key for FTL and make sure they're not bound in-game.