Sorry if this isn't in the right spot.
I'm not sure what settings I should be changing to fix this, I've only noticed it with new ABS that I recently purchased.
http://imgur.com/a/lUND3
When the model is printing top layers on an almost horizontal angle there are gaps between the layers.
This is on a Flashforge Creator Pro, current S3D settings are - http://imgur.com/a/lYGkw
It had the same printing issue on a model of A'Tuin, a turtle (http://www.thingiverse.com/thing:662018/#files), specifically on the flippers and underside of the head.