Hello,
then I don't know if the bug is reproducible, ( I haven't done it yet, and now I can't because the server is having trouble )
so, when I cast the Mage armor spell, and a spider cast the entangling web spell, I lost all my mana, as well as a big sound bug.
I'll re-test that when I can, when I got back, my mage armor spell was no longer in my set.