Optional quest objectives marked failed but

[anonymouselbow]

I actually achieved some optional quest objectives after they were marked as failed.  This in itself is strange to me if it's so rigid, because I couldn't see why it matters.  But, I'm wondering if and what consequences I have accrued if an optional objective is marked as failed.

[Greg]

Can you be more specific about which quests you failed?

[anonymouselbow]

The Gray Cowl of Nocturnal optional objectives:

Find the key on the corpse with the lantern.

Convince Nivenor to give you her keys.

For some reason these objectives were marked as failed but I did get the keys from Nivenor and found the key on the corpse.

[anonymouselbow]

I have since found the console commands to complete quest objectives and quests but my question is specific as to whether failed optional quest objectives make any difference in the results or actions of the game.  I presume they might make some difference but maybe they don't.

[Greg]

The objectives "Convince Nivenor to give you her keys" and "Search Nivenor's corpse for the strongbox key" are optional. The goal here is to get the contents of the strongbox any way you can. It doesn't matter whether get the key from Nivenor, kill Nivenor and take the key off her corpse, pickpocket the key off Nivenor, or pick the lock on the strongbox. You should have just read the Stranger's Instructions that was in the strongbox to begin the next stage of the quest.

[anonymouselbow]

Mostly I was surprised by why the fail optional quest procs so early considering I actually accomplished the quest objective, but I'm wondering if there is any negative result of failing optional quests (ie. do I miss dialogue or some reward bonus).