Some people are simply sensitive to the taste from the type of plastic potable water hoses are usually made from (vinyl).
The simple solution is to buy a hose that is labelled "taste free" like the Valterra one below. Taste-free hoses are made from a different material. There is no filter that will do anything to remove the plastic taste from a regular hose. Charcoal in filters is for removing chlorine odor/taste. Getting an NSF certified is a good idea - not sure if the Valterra is but there are other brands of taste-free hoses out there.