1) are there any 3D layers?
Yes, as a matter of fact – aside from the flag, I have a beveled-edge square map swiveling in, with another layer of one of the countries cropped out, swiveling in with it, and it breaks off to larger scale after they both enter.
2) What is the minimum amount of stuff you can put into the comp to make this happen? (e.g. one layer, no effects?)
Well, the flag (which seems to be the originator of the “line”) initially had the wave warp and drop shadow effects on it – however, once I disabled the drop shadow, the line stopped appearing beneath that flag graphic. However, no drop shadow is present on the text layers, and the line is still appearing under both of those (only effects I’m using there are opacity keyframes).
3) Does it happen all the time (no matter what is in the comp, in any comp, in a new project, after a restart, with any effects) or only under specific circumstances?
I ran into it on Friday, the system was shut down over the weekend, and this morning after starting up, it was still doing it. I’ve only seen it in this project/comp – I’m about to start editing another background similar to this one, so I’ll see if it reoccurs.
“Scratching could not make it worse, and t’were such a face as yours were.”
~ Lady Disdain