carapace plate and ending

[Macizo]

1:
on a quest our party came across a carapace plate, which in the description is half plate but it's stats report it as full plate.

it was decided this was a bug and the armor was left behind. :(

2:
i accidentally left the party after the finding the kids in snakeland quest and the quest was ended. i was able to end the quest alone, and was still paid. i trashed the coin but is there any way to prevent this from happening?