Kohler Genuine 1309116 Flush Valve

Good morning, Since you are asking for feedback, I replaced this valve because the toilet would fill, and then off and on keep topping off. I ordered a replacement valve and installed it and it is working fine. I have three of these same toilets. In the attached picture you can see a bump in the gasket that was not allowing the valve to seal properly. This bump in the gasket was only on the valve I took out. It was not on the new part nor was it on the other two toilets I have of the same model. Your service on sending a replacement was great. I have to wonder if under your warranty if I shouldn't be reimbursed for the cost of the part as it looks like it was a manufacturing defect. Thank you.