Enter/leaveEntity scripts on FBX models


I’ve been experimenting with enter/leave entity script callbacks (loaded from a URL not “direct-injected”).
So far the same script URL works with the primitive geo available in Interface but not with my loaded FBX models.
I’m simply doing a print to the console to check functioning.
Anyone else see this behavior? If not, any ideas of what conditions may make an FBX not work like primitives?