Hi i find this stuff :D
It seemed to happen completely at random to me but always at the start of a mission. I haven't seen it since the 0.2.0 patch drop though. also when running co-op the model shadow didn't show up but a text string place holder did, and it was consistent in its appearance at every mission start. i never could get a screen shot of it because it didn't last long enough. hope this helps
Had this happen once after selecting a mission from the star map, it occurred the first time I started a mission after the update dropped, but I haven't seen a repeat of it as yet though.