I didn't have what I'd consider a ton of inventory. I had maybe four midnight stones and about seven total other items. I will try that though to see what happens.
One thing of note, however, is that I did jump into that dungeon when I first was able to, only to run for my life. The battle I spoke about above came many turns later.
So... is there a bug that causes the quest reward to not be given out if you enter then bail on a dungeon and come back later? It doesn't make much sense because the screen telling me how lucky I was to get the army sounded pretty deliberate. The game certainly knew it was time to fork over the armor, but it didn't.
Here's to hoping it's an inventory glitch.
