Glowstone Ingot and Refined Obsidian Ingots are both unsmeltable in the Tinkers' Smeltery. According to the quests, they should be smeltable.

Am I missing something or is this a bug?

There are special recipes for molten refined glowstone and obsidian, you can't melt the ingots directly unless using Thermal Expansion machines. You need to make them in certain machines and pipe it into a smeltery or transport manually with something like advanced ender bucket to make Osgloglas.

The quest book is wrong and could certainly use some editing though.

I see, thanks!

The quest book is wrong and could certainly use some editing though.

True! Would fix next release.