Many years ago (at a company I am no longer with) the salesheads pressured engineering into a product modification which they them sold to customers prior to a repeat of RF emissions testing to FCC Part 15. My own project had been suddenly canceled and I got pulled into the mess when the subsequent RF emissions testing revealed that the modified product vastly exceeded allowable FCC radiated limits.
After I did much physical and mechanical redesign and got the product to pass FCC testing, sales response was "How do we explain to the customers why they need to make this change? Can't you fix the problem without having to make all these changes?"
To which I basically replied "That's YOUR problem. YOU decided to sell the modified product prior to emissions testing."
The fact is that while the customer is NOT always right, THEY ARE the ones with the money. I have showed customers that the "build to print" they supplied would not work, and that customer was grateful, responding with a PO to make the design work. But not all sales weasels are as cooperative as they were at that employer.