Assuming he’s right, the 2D export is doing its own thing, and isn’t affected by the preferences settings, but screenshots are. I can ask whether the exporter could be updated for higher antialiasing values (at the moment it looks like it is doing 4x), but these are third party libraries that don’t get updated much.
Exporting a larger image and using an image editor to scale down to the size you want, would work around the problem.