Hello Nils,
maybe you an invisible flicker within your feedback system.
You can try to remove this effect by deactivating the manual train follow button, see picture:
One additional thing. Please a (virtual digital address) to each of the locomotives. A locomotive address of 0 (even if not needed for MFX) is no good idea.
And please use the check routine in the program (red exclamation mark). The routes and profiles have several hundreds of errors.
Regards
Markus