Been using Maya for a long time now and this is new to me. I have a character with a cup parented to its hand joint. Everything looks fine in the viewport when previewing the animation but when I render something weird happens. About half way through the rendered animation the cup duplicated itself. The duplicated cup stays stationary in the spot where it duplicated while the original cup keeps moving with the hand like it should. Im new to version 2011 and having trouble fixing this. I tried deleting the cup and making a new one but got the same effect at render time at the same time in the animation...could this have something to do with the joints? Also this problem only happens in the Batch Render and not when I do the Current Frame Render...Is there a script that renders animations from the Current Frame Render window?
I can confirm this bug in Maya 2012 (objects leaving behind 'duplicates' at random on objects in the animation render but nothing else). These are simple objects, not rigged or anything - they don't even have their visibility keyframed! Rendering out a single frame does not cause the issue, but it repeatedly happens when I batch render.
The solution I found was to start at the frame it starts happening (just starting at a frame that wasn't the first wasn't good enough for me). My guess is that it is due to some optimisation it is using to improve render times between frames (the duplicates are always in the objects position at a previous frame).
Shrug - anyway the problem is easily fixed by starting rendering again at the offending frames.
Hope this helps someone, I spent an hour chasing this down.