So, when I am placing certain trains down in surveyor, like the BN RBL Reefer and the PS-2 Hoppers, they work normally, ARN works, not faulty, no errors appear.

But then when I run it in Driver, it suddenly disappears, and if it's connected to an entire train, the entire train disappears.
It gets stranger still. then, if I back another train (that is visible) to it, the train couples like normal and then re-appears, albeit if I set something like loads or open doors, it reverts back to default settings.

Can someone explain this? I have absolutely no idea what is going on, and searches reveal nothing.