Can not target drone because it was dropped by Mimir Z800 in a car

I challenged a MIMIR Z800, thought it was a good idea cause I’ve some nice anti robot weapon modules.
I was surprised when I deactivated the Z800 and it nonetheless dropped its drones.
Anyway, no problem I thought again, because of my EMP grenades.
Here started the problem / bug:
one of the drones was dropped in the field of a car. When I targeted the Z800 and its two drones I could not target the ‘car drone’, although the AOE clearly had the drone inside. I couldn’t target the drone until it moved out of the car and attacked me.