MigrantP,
I am currently playing a game with Legacy, GI Bunker, Ra, Wraith and the Visionary. At this point GIB, Wraith and the Visionary are all incapped.
On Legacy's turn, play a card, use Galvanize.
On GIB's turn, allow Legacy to use a power, Legacy uses Galvanize.
The game doesn't seem to allow Galvanize to stack. It only comes up as a single +1 in damage resolution.
On a related note, Wraith allowed Ra to play a card. Ra played Flame Spike. The ability to use an additional power wouldn't let me use Ra's base power, which he used on his immediate preceding turn. The only power it allowed me to select was The Staff of Ra.
And I am not seeing the option to discard from heroes who have no cards in hand.
It's best to email bugs to support@handelabra.com (ideally from within the game on the credits screen) so we can track them.
I've stacked Galvanize before in the game so it's either a regression or something specific with that situation. If you can email us details with screenshots that would be helpful. Thanks!