Grooming a beard transplant: will there be shadowing or will it look normal?

As you mentioned there is scar tissue as with any other procedure. However, there are a number of things that can be done to minimize scarring such as placing grafts at the appropriate level (so they are not too high up or to low down). The smallest incisions possible can be made that will still appropriately fit the grafts, and the artistry including the spacing, depth, angle, tilt, curvature of the hair should all be considered. Even then everyone heals differently. Some people can be prone to hypopigmented (light) discoloration, hyperpigmented (dark) discoloration, or raised hypertrophic or keloid scars. Taking good care of the grafts by carefully following your surgeon's post-operative instructions and being careful with strict sun protection can minimize these risks, but again they are still possible as everyone heals differently. Generally discoloration (which is what you may be referring to) should improve with time over the months following the procedure. I would discuss this concern with your performing hair restoration surgeon.