So, first the guy in deArnise Keep with the acid component of the Flail of Ages doesn't drop it. It'da been nice to have all three heads, but I'm not sweating it- chalk it up to a glitch and move on.

Then, a little later on in Firkraag's Dungeon I'm putting together the pieces of the burial mask, and one of the 6 genies drops NOTHING. This sets off a red flag, but I (stupidly) think that maybe I'm remembering it wrong and that the other piece will turn up somewhere else in the maze. Nope. I've killed everything in sight, and have 5 other pieces. That one guy didn't drop the item right. Now I can't get past the guardian. BOOoOoo.

Anyone else have a problem with missing drops? Is there a fix? Will reloading and trying an encounter again help?

Reloading might be worth a try, but that's a pain in the rearend. Do you have any mods installed? Something to consider if you can't find any other solution is using the console to spawn the items in,