What about triggered abilities with multiple targets, like Sona, Harmonious?

The same is true of triggered abilities with multiple targets. For triggered abilities, however, this causes some cards—Sona in particular—to work in unintended ways. Going forward, we’ll put the words “up to” on most triggered abilities. In the meantime, several cards are receiving errata so that their triggered abilities behave intuitively. At the end of your turn, if I'm at a battlefield, ready up to 4 friendly runes. When you conquer here, ready up to 2 runes at the end of this turn. At the end of your turn, ready up to 2 runes. When you play me, buff up to two other friendly units. (Each one that doesn't have a buff gets a +1 [M] buff.)