As another Ox/TinyG user, I had similarly strange things happen the first time I tried to do anything with ‘stock’ settings.
I learned, very quickly, that with something like a CNC machine, there is no ‘stock’ setting and that you need to go through the parameters and set them to your machine.
Darned n00bs!
Now, it is smooth and everything works great.
Rhino, definitely recommend double-belting your X*Y axes… for the additional cost of a bit of GT3, it is very much worth it.