This is a really odd one.
Looking at your logs, it seems some .NET 4.7 libraries are being used. System Ninja isn’t compiled or tested against 4.7 yet, so there might be some odd conflict happening there.
Keep an eye over the next week or two for a System Ninja test build specifically targeting .NET 4.7. We’ll see if that makes any difference and if so, we’ll consider boosting the minimum .NET requirement going forward.