Trials of the Braves progress doesn't count if dead

[Nekodar]

I know this. "It's the same for hunting logs" really doesn't make the whole thing any better. I would love to go in and kill "just the boss" if that was possible. But it isn't.

*shrug*
I don't really consider it a bug myself.
Anyway, be happy it wasn't Copperbell Mines (hard) that you had to do again... That one appears in two books, and it's much more of a pain to get through in Duty Finder than any other dungeon (even counting pre-nerf Pharos Sirius).