Yes, minor variations in grout color are normal and not considered a defect.

After grout is installed, you may notice normal color shading variations due to uneven drying and the fact that grout contains natural products that cannot be mixed with absolute consistency controlled during installation.

Grout is porous and, over time, it changes color due to items that come into contact with it: dirt, grease, cleaning products, and other items.

To minimize color variations:

1. Keep your grout clean. Don’t let liquids or other items sit on the grout for extended periods of time. All-purpose cleaners that are excellent for keeping grout and tile clean are available at most stores. Do not use abrasive or oily cleaners.
2. Consider sealing your grout. Consult a professional first. Sealing your grout can reduce color variations but may make the grout look darker. And your installer can make sure your grout has had its required cure time before a sealant is applied.