I’m having some routing difficulties with multichannel plug-ins.
When using Ambisonics tracks and routing and inserting the SoundField by RØDE or Harpex plug-ins, those plug-ins will not automatically be activated with the appropriate routing (routing selection in top right corner is blue). When manually selecting the routing (either 1st order ambisonics or 3rd order) it will, in an unpredictable manner, either activate or not.
The only way I found to circumvent the problem is to insert those plug-ins within an instance of a Plogue Bidule plug-in.
The Plogue Bidule plug-in can be set to either communicate the hosted plug-ins latency to Nuendo or not. When the SoundField by RØDE and Harpex plug-ins latency is not sent to Nuendo, the solution is working, but when the hosted plug-ins latency is sent to Nuendo, the SoundField by RØDE and Harpex plug-ins routing becomes unreliable again.
So this multichannel plug-ins routing problem seems to be related to plug-in latency. This problem is also cross-platform: same behaviour on macOS and Windows.