Hi,
It feels a little misleading that Lightning returns a non-zero value when successfully rendering?
Lightning: CallCurRendererRenderFrame returned code 1
Yeah, we know, but CallCurRendererRenderFrame is a wrapper in Lightning that calls the CurRendererRenderFrame function from the Max SDK. It’s the CurRendererRenderFrame function that returns 1 on success. 
ADSK, you rock! Thanks Ryan!