Can you let me know what card you are talking about?
My Rising Rage card (from the expansion) lets you change green fists for armor (and vice versa).
I don't see a card in the base game or the expansion that says "3 DMG" anywhere on it. Sorry if I am just missing something.
When the PnP demo version of the game released that was the effect on Rising Rage at the time (that post was from Jan 2018). Through continued play testing, after the KS, we tweaked or changed altogether a few card abilities to be awkward to understand or difficult to track.
Rising Rage was one of those cards. The effect you described on your card is the correct version (which is different from the old demo version).