I got the RE from refreshing at spells galore saying I found the volcanic ash, but when i return to Skitters to turn it in I get the old message:

You discreetly hand Skitters your chunk of Raw Obsidian, and he doesn't ask where or by what means you got it. He slips you a note, the contents of which is very to-the-point,

Volcanic Ash, Deaths Cap. Sacred Lands.

You nod quickly and set off on your new mission.

and now the volcanic ash is missing from my inventory.

Same here.

Did you give him a Deaths Cap as well? That step has two items :)

Oh! He don't take them seperatedly? head hits desk