Belt Skipping/Displaced Layers

You might have some garbage in the stepper itself. They have very tight tolerances inside and the smallest piece of metal stuck to one of the magnetic surfaces could cause this.. Just keep using normal speed.. :D

Thanks. If the issues pops up again I'll either inspect the stepper motor or replace it for the time being, printing at normal speed has cured the problem. So, as you noted, that's my solution.

Hy,

I've got exactly the same problem, i've done every thing said here and nothing still the same. Not even one print correctly.