This problem can happen with the best of paints and has more to do with the technique of application. Application by an inexperienced person may result in non-uniform spreading of paint that gives rise to inconsistency in sheen. Not maintaining a wet edge can also result in lap marks which have high sheen. Not preparing the surface and painting over unprimed porous surfaces and surfaces where the porosity varies can also cause non-uniform sheen.
The surface must be primed or sealed properly in order to remove the porosity. Only then must the paint be applied. If you do not use a primer or a sealer, then the paint film will differ in sheen once it dries. Applying a second coat after the first one thoroughly dries may help. Always use a steady hand and paint uniformly. Do not take a break before the entire surface is painted.
Also, apply consecutive strokes of the brush or roller before the previous stroke dries. This is called maintaining a “wet edge. You can also avoid extra overlapping by moving from wet areas to dry areas and not vice versa.