those all bugs are game related and cannot be fixed. This mod is basically a hack of game engine and engine is very limited. All tracks in this game can be flat only. So „slope track” collision is like small stairs, they just look smooth.
you need to do flattening by yourself because in game editor it is defined only by 2 points and that means for all curved tracks it would be big rectangle. For that reason flattening is only in small area so you can get the reference for manual flattening
I’m not adding anything new because game developer haven’t updated tool for new blender version. I have almost ready train but still waiting for an update from develpoers