Do you understand? This is the statement that we're saying is incorrect. The english word cachet is not pronounced phonetically "cachè" in english. There is another word, cachet, in french. It is not the same word. It does not mean the same thing. It has a common etymology, but that doesn't make you the authority on its pronunciation.
You are trying to argue with an American how an English word since the 1600s is pronounced!
I'm not telling you how it's pronounced in French, I'm suggesting how I pronounce it in English using French as a reference. I don't really think an accent aigu sounds anything like an accent grave.
I don't pronounce "cachet" as "cachè" but rather "caché".