Sorry for the late reply on this, I only just noticed it.
What is the original color profile of the image? It should look the same for export if you’re not changing the profile, but I’m guessing that’s what you are doing already?
If that’s the case, then I think there’s something funky going on with the profile in the image. Can you email me a sample at support@flyingmeat.com and I can take a look at it?
(You can also enable the “Match colors to profile” option, but I kind of feel like you shouldn’t have to do that).