I've been using Mjoll for about 20 levels with no problems. I gave her a Soul Trap crossbow and two-hand mace and all my shards and it's been working great till now. For some reason now she's over weight and can't carry a single shard. She's only got Scaled Horn Armor, boots, gloves and her weapons. What's going on? I'm guessing it's a new bug... Any fix for this?

I'm on Xbox 360

Followers have a default inventory that is hidden from the player and sometimes respawns, sometimes giving them duplicates of the default inventory that they are already carrying around (and which you can't take away from them withing modding or console commands).

I don't know when the respawning happens, I only noticed it with followers that I habitually dismissed and then reacquired, and that's a known bug that dates back to release IIRC. But I've heard other people say that they have the same problem with followers they keep and never dismiss, so I dunno. But it definitely sounds like that's the problem here, that Mjoll is carrying a lot of hidden inventory that is causing her to be over her carry weight even though what you've given her isn't that much.

She's actually really, really fat. And the armour works as a girdle.

Her weight doesn't bug me. She's got a couple of pounds on her. Which I don't mind as long as they're in the right places ie Christina hendricks.

On the PC you can enter console, click on her, and type 'toggle BMI.' That sorted out her weight issues pretty fast.

Yes I am taking the proverbial.

Check to see if she's still carrying the arrows that enemies have shot at her, or hasn't picked up the weapons of fallen opponents.