Hi buk, yeah the actual model data is kind of messed up in this case, the fillets on the upper and bottom parts of the holes have messed up trimming boundaries on them.

So I'm pretty sure that the actual bug in this case happened during filleting, sometimes a bug in an earlier stage can make a damaged object which then prevents stuff like getting a good export later on.

I think that the holes are going to need to be re-cut and then re-filleted, were these filleted with the newest v2 beta release? There have been some bug fixes in there which may help in this case.

In case you don't have an older version, I have attached here a version with the holes removed, those need to be cut again but I was not quite sure of the pattern of the cutting curves, can you show me how you did that part?

- Michael