I have converted my CAD data from Inventor 2013 to iges, step, CATIA and Parasolid format for send to my customer. My customer use Solid Edge software. Suddenly when they want open the data, it is broken and some surface are missing.
I have seen this happen on geometry that is complex and has very small bits sticking out from the convergence of merging features. Sometimes these very small bits when converted are not re-interpreted correctly and are dropped by the importing engine as anomalies. Some engines are good at healing small gaps and other are not. If there is a gap healing tolerance on the import side I recommend bumping it up a bit.