With the introduction of vinyl, shading became a problem. With commercial materials, this was easily solved by reversing the material. Only under extreme lighting conditions, such as wall washers, would shading or embossing depth be visible. However, on patterned non-random residential materials, shading can be prominent. In making vinyl goods there is color variation from side to side.
Every vinyl exhibits shading under the right lighting.
Whether or not this is acceptable, only your client can say. Material work-arounds do take time. Certainly, you and your client are happier with the project completed. This additional time should be built into every job. As a bonus, there are fewer surprises at the wall.