The treasure says that her cannons will fire twice, but the one that comes out from her battlecry (or at least the gold one from one of her ‘higher’ portraits), does not.
I’ve had her attack the leftmost unit multiple times with the battlecry cannon and one from using her ability up and only had three cannon shots fire from the two. The same is true for the cannons firing at the end of the round - two from the ‘grey’ ability summoned one, and one from the gold one. Not sure if it’s a ‘gold version’ bug or a battlecry bug.
, a lot of which have persisted for quite some time (let alone proper documentation of them), so… I suppose we’ve got to be patient, maybe it will be addressed one day.