Err... At least for the time being, I don't think I want to pick up maintenance on another fairly complex/involved mod, to be honest. I was a big fan of construction drones back in the day, but I haven't used them much personally in last couple of plays since they kinda end-up being a bit too overpowered.
As for your troubles - there was a couple more forks of this mod, are any of them behaving better in this regard?
Have you considered switching over to Klonan's own spiritual successor - Companion Drones? (although, not sure if that one might face the same issue in combination with Construction Planner).
Best regards,
Branko
P.S.
Btw, this is exactly how I ended-up picking up/forking a couple of mods out there - so this could be your chance as well :D