A file that exhibits the issue is here... http://www.cdplusg.com/Gimme.zip
It is a multichannel Apple Lossfile file with .mp4 extension.
Track title was modified with the following script. Some parens need to be quoted didn't know how to paste in here without losing them.
$if($and($in(%title%,(5.1 mix)),$in(%_recordingcomment%,5.1 mix)),$set(title,$replace(%title%, (5.1 mix),)))
// Add recording comments except on some generic types
$if($and($ne_all(%_recordingcomment%,,original studio mix,original studio,original studio master,officially released studio recording,catchall for unidentified versions),$not($in(%title%,%myrc%))),$set(title,%title% (%myrc%)))