The only other things I can think of are either...I put the drones in my faction, and verified the push beam was set to 100% effect strength before firing. Not moving, no turrets involved, and no collision damage. I honestly think they hate being pushed. I'll have another chance to test tomorrow, though.
- the drones are pointing towards your ship so they ram you by default as their speed boost kicks in.
- The boost computer is ending up facing your ship, funny how they work but I have noticed they add velocity in whatever direction the computer block faces. Could be an issue.
- The skooms are disabling each other and thus end up ramming you before they get a chance to reorient.
Try to check those when you get a chance, if none of those are the culprit share a link to your ship with loaded skooms and I'll see if I can get it working.