So, found a REALLY major mistake, Cliff. I found some code re-use! An error message! When there’s an error with saving a unit, the message SPECIFICALLY SAYS:
“SHIP”
Ah, I knew there was a line of code I re-used somewhere 
It’s amazing (and annoying) how little of the GSB code survived the change to GTB tbh. The minute stuff has collision detection and shadows, the whole GSB engine falls apart. Plus the GTB one is much faster :D.