It's highly unlikely that your priming agent -- even DME -- would have such a significant impact on your flavour. Posting the recipe and your process would be a great first step towards troubleshooting.
Fermenting: American Stout
Kegged: Biere de Garde, Premium American Lager, "May Day" Belgian Pale Ale, "Witty Retort" Light RyePA, "Spring Break" Marzen
Bottled: "Sh!tshow" Schwarzbier, Maibock, Saison, Kolsch