Mono events mute stereo events and vice versa in Nuendo

I am testing the SpectraLayers Pro demo and have a weird behaviour in my nuendo project which i dont understand:
If i edit both mono and stereo events with SL in the nuendo project, the edited events seems the become part of an exclusive group in playback:
Stereo events only play when the last selected event in SL was a stereo event.
Mono events only play when the last selected event in SL was a mono event.
Events that are not using SL are always playing (as it should be).

Stereo and Mono are displayed in Nuendo as if they were two projects in standalone mode.

It seems like a bug to me, but also a bit unlikely that nobody would have reported that long ago. Am i using it wrong?

Versions: Nuendo 11.0.0 and SpectraLayers Pro 7.0.20

The same has been behaviour has been reported in the german forums in Cubase:

A workaround according to that thread is to convert everything to stereo…which is a workaround, but not a solution.

As others have problems with this too, i guess this is a bug.

Any comment if this is on the Cubase/Nuendo side or in Spectralayers, @Robin_Lobel?
(btw. tried 7.0.21, still the same)

Well… my demo version will stop working soon.
Steinberg reminded me via (automatic) mail to buy it before the demo runs out - but as i got no response here or on my bugreport via the support system, i will not buy it…

I will reconsider it when the bugs are fixed.