^^^^^ this is true..........too aggressive with dry burns or building your own coils and having a hot leg can torch the rubber and that taste will not go away without replacing it.
However, I think that all "new style" Kanger coils have the silicone grommet instead of the rubber and knurled chimneys. If it is not, you likely have a knock off because I haven't bought any real Kanger coils in any resistance without the silicone.