Same goes for Healing Wish. I feel my gameplay will have improved once I properly learn how to utilize HW for extended rounds.Was that the first time the Ursaluna had hit the field, or had it been chipped earlier?
So without seeing the rematch, my hypothesis is that after Cresselia fainted, they sent in something totally healthy which didn't use up the Lunar Dance (perhaps to set something else like Screens up or to weaken a Luna check), which you fainted without another weakened mon coming in after, and then they went into the Chipped Luna being the heal recipient.
5 Turns is quite a time for that to last, depending on how it interacts with Hazards
On the flipside, you can easily accidentally get the wrong one. These moves feel like a skill ckeck