I got it: My Squad stopped moving when one of them was KIA, then I talked with any of the members not moving and boom; they followed me again

Hope this helps anyone

I found a solution on the Bohemia forums. Sometimes when ordering my troops to stop following whenever I was disembarking from a convoy, I would receive this "Stop" order beneath my name. If this happens for you, the solution to fix it is to press 0-1 ( issues the "done" command ). Which will then allow the AI to continue following you.

The first time I used the AI named Snake, every time I used the U key to team switch, as soon as I was "possessing" the other team member Lt. Barnes would bark out a bunch of nonsensical commands all by himself. His commands sent some of the men running for the horizon. I don't know if this glitch was caused by some problem in Snake, or if your team can't have more than 8 or 9 members, or what.