Patches on newly plastered walls painted with watered down emulsion then vinyl matt

Hi After the first thinned out coat was applied did you use a good quality emulsion farrow and ball paint after a mist coat (the thinned out coat) is applied always takes 3-4 coats to get a solid finish where as Dulux after mist coating is 2-3. Did you use a medium or long pile roller as short pile roller sleeves can cause this affect. To get over it is use a medium long pile roller sleeve and apply 1-2 moor coats of a good quality paint Dulux is a good quality but try and get Dulux Trade nor the retail stuff from home base or B and Q. Hope this helps Alex