cheezz, I keep the unopened jars in the frig, simply because of the butter. I had one batch go bad
a few years back that I had stored in the cabinet above my dryer. Turns out the vent hose had pulled away from the wall and the heat was going straight up and into the cabinet. Lost my 5 kg slab of gianduja (oh, that was a sorry, sorry day) and two Dyslexic jars has a bit of mold on the top. Couldn't tell you how long it took for that to happen.
They seem to be okay out of the frig for at least a week's shipping time. At least no one here has ever told me different. Has anyone had a problem??? Please add to our knowledge base.
As noted on the label, keep the OPENED jars in the frig as well.