To perhaps be clearer - the void process reopended the invoice but where?

What does the manual check register show?  That would give the best clue as to what happened.

It shows the voided check to NOF vendor but also shows the deleted vendor number & name, under comment it says 're-instated invoice'.  If I try the deleted vendor number it asks if this is a new vendor, so it will not let me access the invoice there.

I'm inclined to make a journal entry to AP to remove the amount but I"m concerned that the invoice is lurking somewhere, even though it does not show up on any report I run.

You might try recreating the vendor master record and see what happens.  I don't think it could hurt.

If in doubt, make a backup copy of your data and try it in the backup company.

I had to move on so I made a JE to get the amount out of my AP GL account.  The AP trial balance reconcile

s with the GL - for now anyway.