Until this update, if you beat the Dungeon Boss within the time given you completed the dungeon, even if the catching animation ran long. Now, at least in the Orre dungeons, you can fail to complete a dungeon while catching a pokemon. I even had (just a little) more than a second left on the clock and still failed it.
I just tested it on another dungeon and either it's harder to purposefully replicate than I thought, or it's specific to shadow pokemon/Orre
I have confirmed with one other player that this is not just my personal game, this is a thing that happens
#Dungeon fails while catching the (Shadow specific?) Dungeon Boss
timber lynx
Dungeon fails while catching the (Shadow specific?) Dungeon Boss
velvet blade
it probably counts it as failing to defeat a trainer