Steppers always(*) skip if you try to drive too fast or accelerate too fast. The mechanical load
is a strong controlling factor so you have to measure the maximum speed and accelerations
that allow reliable operation. Little thing called the laws of physics at work there.
(*) Having said that I have an ultra-miniature (6mm diameter!) stepper than can go from 0 rpm
to 2400 rpm instantly, but its moment of inertia is many orders of magnitude smaller than even
a 28BYJ-48....