@cam11 - thanks for your reply.
The issue for me had nothing to do with any of the SSL software, drivers, etc… - it was a temporary bug that cropped up in the v11.0.20 and lower builds that caused conflicts with specifically the ipMIDI driver itself. Confirmed this - my other DAWs on the same system didn’t exhibit any errors at all with ipMIDI and the Nucleus as a while.
Cubase v10.5 and now Cubase 11.0.30 and later builds are not affected by this bug. Thankfully, as I mentioned, this issue was ironed out with the release of 11.0.30.
We can thankfully post this as solved/fixed.