The same thing has been happening to me with the taste disappearing, or starting to taste weird. I'm smoking hydro e-cigarettes because I'm from New Zealand and they are the only ones containing nicotine that are currently available here. (I've ordered some from overseas but they are still on their way) anyway I've found the menthol flavor started tasting really weird and gross after vaping it for a few days. I tried changing the cargo user because I thought that might be it, but the new carto tasted the same.