An official carbon dating on the Shroud of Turin dates it near the time of the Knights Templar

Not quite.  First off, you’re mixing up the de Charny family and the de Charney family.  Geoffroi de Charney was the Templar commander of Normandy, the one who was burned with Jacques de Molay.  Geoffroi de Charny was the guy who announced to the world that he had the Shroud.  They are two entirely separate and distinct families.  There is absolutely no sign that the two families were connected in any meaningful way, or that the de Charny family had anything much to do with the Templars.  All of the legends connecting or combining the two families are of recent invention.

The Shroud first appeared in Constantinople sometime in the 1100’s AD at the latest.  Robert de Clari, one of the people who mentioned it, writes of it (in his La Conqu

And I have seen discussions about the possibility of a fire (which actually singed the Shroud) throwing off the carbon dating.  That and another discussion concerning some of the pollen found on the Shroud having come from a weed primarily found only in the Holy land.  (Not that I actually believe Christ left a photo negative or anything… just makes for interesting conversation.)