Following up from the post in September, for this particular project the issue ended up getting addressed by doubling the thickness of both petal1 and petal2, which also aided with having scaled down the model to 80% of the original size. Ultimately the issue was perhaps as much related to under-extrusion as any rendering bug (many thanks for the patch however naruf!).
In any case, the completed Remix is now available here:http://www.thingiverse.com/thing:618490
We've added an embedded Arduino microcontroller, servo motor, and RGB LED to emmett's original design.