Ekbab, the Ancient Seed, boss not respawning

I barely beat the two bosses in The Bone Pits. Me and the second boss basically died at the same time (I killed him a fraction of a second earlier), but he never dropped the quest item and other loot. I have tried restarting the map and the game, but still no luck.

Here are some images that might help. I'll keep this post updated, and see if it gets fixed any time soon.