I'm sure they did the thing all KTM people are supposed to do to a new KTM, which is Loc-Tite it on (that and the shift lever). If they used red Loc-Tite -- and from the sounds of it they did -- then you probably need more heat. Propane doesn't generate that much heat relatively speaking. Gently heating with an oxy-acetylene (aka welding) torch is probably what you'll need to do. Just be sure to not use too big a tip and keep the torch moving so you don't get a concentrated hot spot, thereby melting the aluminum lever.