Can you please provide the XML files. We are checking and will be back soon.
The border bug (second one) will be fixed soon.
About the first issue, waiting for XML file from you, if possible.
Finally, nothing missed by you for creating semi-transparent pies. Actually, when 2 adjacent pies are both sliced in, their common inner face(s) doesn't exist (or are invisible) ... they come in existence (or gets visible) as soon as these pies get detached by slicing out of any one of them.