Could you post a video?
I have never encountered such behavior and have 600+hours in this game.
With my last described method it surely works. Pnb have no hitbox then and will move to the place you direct it to.
Make sure you don't have the enter key (modular building) activated.
If this is done a simple right click will put the pnb in place. It will not move by itself. Or at least never heard of it before, neither happened to me.
Probably you miss click somehow or hit right ctrl again or have modular building on. Something that way i guess