LW 1.1 PC, this behavior makes sense, I'm just calling attention to it in case it's not consciously intended.
A reinforcement pod with MECs dropped first on an invasion, the MECs went on Overwatch, another pod walked in and activated, I think this caused one of the untouched Haven Civilians to move and avoid them, which triggered Overwatch. As a result I lost two civilians on that turn out of my control. It's probably a rare enough occurence that it'll be kept in though.
I suppose what might seem odd is that the reinforcements come in and overwatch first. Maybe they should only overwatch after the enemy turn resolves or drop in last. Maybe not though.