Weird interaction with Gwenna, Eyes of Gaea and Battery Bearer
There seems to be a bit of interference when Gwenna, Eyes of Gaea and Battery Bearer are both on the battlefield (and controlled by the same player). With Battery Bearer in play, I cannot tap Gwenna for mana using its own ability - I can only tap it for colorless mana with the ability granted by Battery Bearer.
When I mouse over Gwenna to activate its ability (see attached image), I am shown two options and an alert - the colorless mana ability that I can use, a blacked out ability that I cannot use, and a question mark alert that seems to do nothing.
Do note that Gwenna, Eyes of Gaea still has its mana ability, but I can only use it if autotapper cooperates. This led to me making some awkward plays solely to force Gwenna to be required to cast spells.
Got this myself as well