I was the original owner of this watch. It's true that the reference 6817 is rarely seen among the flagship labeled watches, but those exist. I bought it in a small Swedish auction house and it appeared to be a one owner watch, not running with a really messed up strap. The flagship font looks correct to me, when you compare it to the common 30L flagships e.g. ref. 102. I have no other conclusion than that this model left the Longines factory with the Flagship label.
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