In 2013 I purchased an exterior solid mahogany front door with 8 glass panels. The door contractor stained, sealed and hung the door. It has been sealed regularly as needed to protect it from the sun and elements. I live in Georgia. The last time it was sealed was May 2021. A few weeks ago I noticed 2 oval areas on the exterior where it was discolored and wood was rough. Those areas are on either side at the bottom where the bottom horizontal panel meets the vertical panel. The door contractor Has not responded to my emails. Don’t think it is under warranty. Is this due to a manufacturing defect? Any advice?