Test rendering some stuff and full 1920x1080 revealed this black vertical. There’s no geometry there and it’s not a ‘transparent’ edge sneaking in. Any tips appreciated! Full sized but jpg for MB. Appears about 1/8th the way in from the left.
Well … what is there? 
Wondering if it’s a rendering tile. CPU rendering on laptop. So it might be exactly 1/8th since that’s my setting. I’ve never seen render tiles do that before.
I’ve only seen these artefacts with UV post mapping to a plane or from bad alpha edges on painted planes. No idea why it would appear in the middle of a shot? Could it be a GPU issue? Can you try CPU vs GPU?