[Darryl Ramm]

Yep, pretty useless fuzzy screenshots. DUC's cheap and nasty image downsampling settings makes all this frequently useless.

But there is not going to be any mystery or bug here or much others can do for you. You have to find it yourself, and likely if you are having trouble finding it you might be misunderstanding the Pro Tools signal flow, so test/experiment if in doubt/to understand that flow.

First make sure there are no hidden tracks, that's the easiest stuff.

You going though muting tracks.. but any pre fade sends won't be muted (post fade will). This is a common cause for problems like this. And plugins are not muted, they still process signals... which in some cases (more VI ones) can cause confusion.

So when you mute all tracks you still hear stuff? That will be sends messing with you.

If debugging all the sends/bussing is getting too much for you you can make tracks inactive which absolutely stops them playing anything off disk. A binary search there should be relatively quick, find the spot where the ghost vocal is, disable half the tracks, disable half those if it still appears, enable half the disabled tracks if it does not. etc. Also just attacking this from a bus viewpoint might help, e.g. going though and muting all sends to busses etc until a particular bus is totally quiet should help.. then go to the next bus and repeat until you find a bus the ghost vocal is on... it's likely not coming from a direct track if you have muted them all.

Edit: got all confused writing about the bus suggestion, I meant listen to each bus separately (assign it to an output by itself and listen to that bus) and if you hear it on that bus then go mute the sends and tracks going to the bus.