I think you'll get problems with going to morph from native archicad elements too. At least I recall this happening when I tried to make one big morph from a building for a quick site render, the roof tiles and such were no longer properly alligned.
So it might be more of a problem with morphs rather than the imported format.
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nlArchiCAD 9-26NED FULL
Windows 10 Pro
Adobe Design Premium CS5