Followed the advice to just use WMA format and then converting to mp3 before sharing with others. Also been rendering a separate BIAB safety file (i.e.; TUNENAME-wma) so that the master doesn't get buggered up.
The error is still there when just setting up any tune using a real tracks style and rendering to mp3. Even unchecked include audio. So no idea why this is suddenly a problem (hmmm, wonder if updating to build 386 had anything to do with the problem showing up).

Still a few bugs to work out but project is pretty much back on schedule. Thanks for the help.....