Thank you for your interest!
This code was a part of a pilot for a part of the c# application that we did a while ago. The Machine learning modelling was mainly done by a collegaue of mine in Python, while I provided C# bindings, so that we can reuse some code.
Unfortunately, I know next to nothing about Machine learning and Gradient boosting, so I will not be able to answer the questions and issues about that.
This code is here because there's still no official C# binding for the LightGBM, so that it can be used and improved.