I lied.. Problem still persists. I guess I'll be filing a bug report with Choasgroup. Has nothing to do with substeps.

Tonight I'll be rebuilding the scene again and running more tests. Then I'll send Choasgroup the scene file.

EDIT: If anyone is willing to test mybase file that has a Vray 3.1 render farm (with Vray DR) l would more than happily dropbox it to you. For all I know it could be symantic antivirus messing with something.