Hah - me too. Walk back from dropping off the kids at school, brain chuntering away over the quests I wanted to finish up today

Had a funny thing happen last night. I won't name specifics as they're by the by really and naming names would make it spoilerific. But suffice to say, at the end of one long quest chain that started at the beginning of the game, I rescued a certain character and reunited them with a certain companion. I was given various choices, varying from 'kill them' to reconciling them completely, which I chose to do.
"Well then, I shall see you back at home where all this mess will be sorted out!" they cried, and scampered off.
Great, I thought. That was a satisfying conclusion.
Not three seconds later, a window pops up telling me that quest has been updated. Let's check out what it says, I think.
"X is dead" reads the new entry.
I think WTF and prepare to launch into a diatribe about broken quest chains, but retrace my steps to see if I can figure out what happened. Not a dozen feet from our heart-warming reunion scene, the character is lying dead on the floor. Turns out they'd run slap-bang into a cloud of death-fog I'd accidentally released during an awkward fight to reach them.
"Bollocks!" was my first thought, followed by a wry chuckle. Whoops.
I could have left it as it was and I suspect nothing from then on would have been any different, but having chosen to let them live I wanted to see that through, so ended up reloading to a previous save and having to re-do the aforementioned awkward fight... this time being bloody careful my aoe attacks didn't catch any deathfog barrels.

My face is tired.