in Nuendo 5.1.1. (PC 32 on XP) I found a bug importing 3.0 interleaved files via drag and drop.
When Nuendo has to create the channel there will be a message about an unsupported file. It will place the file on the newly built track, but it will playback as digital garbage.
When creating an LRC track manually prior to importing via drag and drop Nuendo will not give an error message and the file will play back just fine. The 3.0 files were done by Nuendo itself btw.