Challenge/Complete these Missions: Revive a Bone Bird for Catarina

The background:
My second mission for Catarina involved a Bone Bird, and I wasn't entirely sure what she was saying, other than that I would have to make it 'go to sleep' at her latest sculpture. Said Bone Bird appeared, and together we headed off to a yellow sign on the map, where I found a bloody mess of some sort. Was that her newest work of art? No, it wasn't, but I didn't know any better, so I stayed there until I managed to let the occasionally appearing skeleton archers kill the bird, whereupon I failed the mission. Very annoying, and it was only later that I discovered that her newest sculpture looked exactly like her last one, and it was standing all alone in a cave on the other side of the map. So I'm looking forward to getting that mission again some time, so I can figure out what I'm actually supposed to be doing.

The bug:
In my Challenges/Complete these Missions menu, "Revive a Bone Bird for Catarina" is marked with a green check, as if I'd succeeded with the mission. But I got a failure message the one and only time I did it. Or are the challenge-missions not the same as the actual missions, and just having had a Bone Bird is enough to 'complete the mission', as far as the challenges go? In that case I guess it's not a bug. Just a bit confusing.

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Gillsing wrote:

a yellow sign on the map, where I found a bloody mess of some sort. Was that her newest work of art? No, it wasn't,

Based on your description, it was just a shrine. Strange it was used though, but since 1.3 I've found a couple of used shrines in maps while playing solo, so maybe it is a feature.