It’s present in my ProRes master file. So, rather than going through several hoops to get the source fresh, I just did a crappy shape mask to copy a different portion of the frame. Looks seamless, and took hardly any time at all.
To offer a similar sentiment to Rogueleader above:-
‘Work smarter, not harder’
So glad you managed to fix it and it not be a big deal.
Just out of interest, do you know what it was or what caused it?