I keep experiencing a bug wherein Marcurio will have a pair of spells "unsheathed" but nothing will actually be in his hands, and he becomes completely combat inept. Sheathing or unsheating my own weapons/spells has no effect, as he just stays there. So far, the only fix I've found is moving to a whole other cell.

Any advice? I really want him to be a worthwhile companion (and I paid five hundred gold for his service!).

youve tried dismissing and rehiring him?
if on pc, try disable - enable.

Yes, I have done that, to no avail And I'm on PS3, so no console code fixes (moarsadvaultboy).

I have had this problem but not with a follower but with my own character it started with 1.5 i just reload a save

I actually started this exact thread a few days ago, but forgot to check it and now it's probably 100 pages back.

I have had the same issue with Marcurio. What I have found seems to work is going through a load zone; he'll reequip and fight as normal.

I don't know what causes him to flip out in the first place, though.