Hi Athrasis.

Glad you like the map!

Not familiar with Affinity, and to be honest, its been a looooong while since I've looked at the map. It seems that the Northern forests were done in a different way to the southern. They're a pattern fill with a mask, instead of a pixel layer (I was learning and trying a lot of different things at the time!), and I'm guessing that's what Affinity is having an issue with.

I've uploaded the pattern (link here) See if you can get anywhere with that. If not, I'll see about converting it to a pixel layer, and uploading a 1.14 version.