auto-save bug using Illustrator for the iPad

I seem to have run into an auto-save bug.

I'll be working on a drawing. I draw, I tweak, I make new layers, draw some more... and then, when I return to the "Your Work" area, my changes aren't saving. Or more accurately, they seem to be saving occasionally. I tried duplicating the file, same result. New files seem to be working? Its inconsistent, and unclear to me what is happening. Illustrator 1.0.0, on my ipad pro 12.9 inch, 2015 version.