I’ll normally spell Cinsault with the “L”.

If you’re wondering why there are different spellings for the same grape, it’s complicated.  Basically the short answer is that Cinsault is considered an ancient grape and while DNA testing for wine grapes is happening more and more all the time, scientists and researchers are still struggling to find the ancestral home for a grape that is widely planted in France and is one of the official Rhone red wine grapes.