Direct offline processing does not work with certain files


I have a problem with the tracks of the multichannel files from the CANTAR X3.

After the import (e.g. via the Field Recorder Audio Import), I can basically only edit the first channel with DOP. There is no processing at all for any of the other channels. And when I click the preview button, changes in the EQ are not audible. Unless I’m using a stereo plug-in! - Then it works. Unfortunately, that’s not the solution yet. Because, for example, the iZotope RX Connect works as a mono plug-in, so to speak. So I can’t use the RX.

Do you have any clues as to what could be wrong?

Nuendo 11.0.20 Windows 10.

Best wishes