Like everyone else I have been having problems with these issues and here is a fix.
I don't have a clue if anyone else thought this, but I have not been doing a lot of GECK modding.
Having read a few topics that said moving stuff out of mulibounds fixed rendering I looked for a
command in the GECK ini. I found the command to disable multibounds and disabled it.
After, everything worked!
What you have to do is find your GECKCustom.ini and change bUseMultibounds=1 to bUseMultibounds=0
I have known this for a week, but I have been pretty busy so I have not had the chance to post.
Thanks.