You are a team leader (player unit) and have an AI team with you (all playable). You order the team to move to a position. Once they are at the ordered position you switch to unit 2 and start walking to an other spot. The AI unit ranked below unit 2 (thus 3) will move with unit 2 instead of staying put at the location as ordered by NR1 (player). Same if you switch to number 4.. then nr5 will start to follow nr4, while the player character (team leader) ordered all units to move to a specific position. And sometimes if you switch to nr2 the whole team will keep folowing nr2, while they were ordered to move to an other position by Nr1. *This is all with the 'move' command, not 'hold' command. It seems that the player order is not the final order for all units, but dependent on what the rank below does. So in practice you can not switch units for manual positioning without giving as team leader/player to command 'hold' first after the move order. They will ignore the move position as soon as you switch and start to move with an other unit.
This also can cause issues if you play a coop mission with an AI team that has only NR1 and NR2 as players. no matter the 'move' orders of Nr1 AI will move with nr2.