[Speedslug]

Are you certain that the hose from the propane to the torch is a "type T" ?

If it is made for acetylene the propane will cause it to disintegrate from the inside and that causes it get gummy as well.

Also even if you do always turn it off at the tank and burn off the stuff in the hose you should still disconnect and drape the hose to drain once a month if you torch every day.

Think of the smelly stuff as condensate on the inside of the hose.
It still needs to be drained and dried if your are torching often.

Also if you swap out propane tanks you can wind up with crap in the bottom of the tanks that can get stirred up and fed into your hose.

A third point is the age and type of regulator; If it is not made specifically for propane the rubber diaphragm on the inside can get attacked by the chemicals in the propane.
And the regulators also need to be rebuilt every decade or so if they are the expensive kind or just replaced if they cost less than $200.