This is a copy from : http://steamcommunit...57398968788430/
As it just happened to me, and I was able to reproduce and confirm, I'm copying the report here (credits goes to Minera)
A very easy to reproduce error.Unlucky for me it happened to some items I would have liked to keep.Short description:When dismissing a follower while on top floor of the inn inside your stronghold all non-equipped follower items are deleted permanently from the follower being dismissed.Reproduction scenario:Go to the top floor of the inn in your stronghold. Put items in the inventory slots of the follower you are removing from the party. Press H (to open the stronghold management page). Press the side tab marked "party management". Dismiss the follower from the party and press accept. Go back to party management. Put the follower back in the party and press accept. All non-equipped items that follower had are now gone forever.It is not a giant problem because it is so localized, but since there is a really big risk you will actually dismiss followers in that very room (to see them in their rooms) this could affect most players at some point. And the items are gone for perpetuity.Edit:Just checked and it seems all quickslot items also get deleted when the error occurs.Edit 2:I am told this also happens if you dismiss followers in other inns beside the one in the stronghold.