Every now and then when I use my propane grill my food comes out tasting like propane. I am wondering why this is and how to correct it.
@Ross Ridge's comment implies that it can't happen, but it is happening.
That suggests incomplete combustion (since it IS getting on the food), which suggests either the fuel air mixture being set wrong, or being upset by having dirt/spiders/mud-wasps/etc. blocking the air intakes. The flames should be pure blue, no yellow (some instructions say "pale yellow tips") when the air mixing is set correctly. Any thing that blocks or restricts the air intake will tend to leave the flame fuel-rich, with yellow or orange colors, and all the gas may not be burned.
To solve, clean the burners completely, find the adjustment points for air (generally just after the gas orifice) and adjust for a clear blue flame. Your grill instructions should describe your particular version.
I'll still stick by the ultimate solution being charcoal, having tried it both ways. If you get away from the compressed coal dust briquettes, real wood charcoal is actually quite fast (which was the hook the gas grill folks always used to attract people away from charcoal)