It must be motion controller related.
My project was also pure c++ and nothing like that happened during motion.
The hand mesh looks almost like it’s getting a double transform while in motion.
The motion controller itself also has no transform node if you haven’t noticed. Only scale is accessible.
I’ll need to do a test directly with the motion controller.
Also I noticed you are using live coding. Maybe it is interfering with the correct compile. Lot’s of things break with it as many elements do not support proper hot reloading. Try disabling live coding, closing the project and doing a proper recompile.