So i've found a trail bug and how to recreate it, strangely it only works in this one simulation i made, it's probably something i did but i can't figure it out. Anyway, to recreate, open the simulaiton (posted below). Turn strange forces on, 'j', and then auto-orbit and auto-timestep (although those may not be important). Trails should be on. Then, run the simulation for a few seconds. When you press space to stop, the trails are printed onto the background. move around the camera and this becomes apparent. Press space again to continue the simulation and the trails return to the object. Strange.