Rendering a lot of frames

Well I haven't posted in a while because not much has been happing besides rendering frames.  It was going smoothly until recently I ran into the weirdest/dumbest problem.  I was rendering several hundred frames of the camera walking around the queue before going in the mountain.  Randomly the bars, reflections, and other objects disappear frame by frame by frame.  Like a train wreck unfolding before my eyes!  

Well I spent a few weeks/months scratching my head and couldn't figure it out.  It eventually seemed to have fixed it's self...Only that it didn't.   So I decided 2 days ago to just make the camera turn farther to the left so that you don't see those items disappear.  Hopefully it does the trick.  I really want to get these frames rendered while it's cold so that my computer doesn't get as hot.

I was able to get these images out of the garbage to show just how weird it is.

UPDATE: I've actually lost the photos again when moving between back-ends, sorry.