I exported a class that contained a datatype matrix with 10 columns and then imported it into the same eZ publish version (3.10.1). The import corrupted the matrix colums, only created two and misnamed them Col_0 and Col_1. I inspected the pacakge and it appears to have exported the information correctly, just failed to re-import it. I'm happy to provide the package privately upon request if needed.

Steps to reproduce

Create a class that contains a matrix class with several columns and then export the class as a package.