Hey Wunkolo,
Thanks for the reply again, I'm using macOS Sierra 10.12.6,
After Effects CC 2017 14.2.1.34 — do you think this is the root of the problem?
I've purged the cache and tested a new comp but no luck, fortunately being able to render
from after effects directly and converting afterwards is working okay for this project,
I'll update After effects when I can to see if this resolves it.
Thanks!
H