If you send the .moho file to
support@lostmarble.com (or upload it somewhere) I can tell you more, but it looks to me like non-closed fills. There are a couple situations in the current beta where Moho will allow you to make an "illegal" fill - one whose outline is not completely closed. We are working to get Moho to prevent these fills.
When Moho draws these shapes, it recognizes the bad part of the fill and doesn't draw it. In Flash, however, a fill can basically "spill" out of an outline if it isn't closed, and you get this kind of result.