Some variation in texture on drywall surfaces is inevitable and can’t be avoided. Minor variation is considered normal and not a defect.
Like many hand-applied surfaces and finishes in residential construction, drywall texture varies with site conditions and by the installer who applies the materials. Additionally, as home designs continue to evolve to include higher ceilings, larger windows, and more lights, there is an increase in shadow casting and light deflection across wall and ceiling surfaces, making even the smallest drywall texture variations more pronounced.