Lately I've had a strange duplication glitch. I think it involves the mannequins.

So I have had Harkon's armor on me (not wearing it, but carrying it) for some time, as I kept it as a trophy, and finally had an appropriate place to put it up: on a mannequin in Solstheim (all the mannequins in my Hearthfire home were taken up). I also decided to put my new Dragon Priest mask (Zahkriisos) on it as well. Well eventually I find out that I have two of each. I don't know if this was before or after, but whatever.

And now I come back to my Hearthfire home, where I've been wearing my Miraak attire for some time, and find that the mannequin where I put all my Miraak stuff when I put on my Nightingale Armor to go do the quest Darkness Returns has an extra pair of Miraak Gloves and Miraak Boots.

Weird. If only I could get an extra Miraak Mask, that'd be awesome.

Has anyone else experienced this?

I haven't, but whenever I drop an enchanted item on the ground and pick it up or have my wife pick it up, an unenchanted clone will be laying there when I come back later.

You've never heard of the mannequin glitch?

I've heard of it, but it hasn't happened to me in Severin Manor.

It's a known mannequin glitch. More than half the mannequins will duplicate the first thing you put on them, except for certain 'unique' armors. That's probably why you only got the boot and gloves and not the robes. Some people like it, they sell off the duplicates, some don't like it or take advantage of it. I know about it, but prefer not to exploit the glitch.

Another glitch is that when you put something new on one, you come back later and find the original stuff equipped on it again. Activate the mannequin inventory and you will see both sets of what you put on it. The only way to fix this, is to equip the 'new' on over the original, leaving it there. You will probably have to do this a couple of times before it stabilizes.

Crazy I know, but it's a glitch you can live with at least.

Edit: happens in the vanilla game and the DLCs.

I thought they patched it though

I never heard that, but apparently not. After my first experience with it, I was most careful about what I put on any mannequin. That first time I put on a set of the cheap plain vamp armor just so it would display something. I must have ended up selling about 20 sets of that armor before someone told me how to fix it. Very annoying! Now I wait until I have something to display that I don't plan to replace! I tested the DB mannequins right away, at least one of them, so I take the same precautions with them now too.

Come back in, and I have Miraak's Gloves and Boots again. Along with my fourth Solitude Guard helmet.

So now that mannequin is screwed?

This has been happening to me, also. I didn't really notice it until I dropped some dragon bones and scales in front of the mine in Raven Rock and the next time I ran up that way to finish off a dragon, I stumbled over them. I thought that this was quite serendipitous, so I dropped a Daedric bow and more more dragon bones and scales, and sure enough, the next time I checked there was another bow and some more bones and scales. If I needed gold I would drop all kinds of expensive unenchanted items to take advantage of this. I already knew about the mannequin glitch, but not the item dropping glitch.

No, read my post, #5, for the fix.

My Mannequin in Markarth always seemed to do this the best for me.

I've wondered something, since I never tried it with those:

If you put something like Marwhatever's armor on it, which comes with lame enchants,
is the duped version the SAME?

OH I think it is the same, since I remember duping the Ebony armor for the daedric
achievement, since I'm short for that achievement due to stupid "bugs" and
picking the goody-two-shoes route on a couple of them (even WITH getting the
two Hircine beast hunter daedrics...) I was hoping duping the ebony would
make it count as another daedric artifact.. but no =/

they did but hearthfire un-patched it...it seems that so did dragonborn

sadly it doesn't work with the jagged crown and a few other items but i'm happy i found a way to keep it and finish the war

I left a mannequin open in Severin Manor just to purposely try and duplicate Miraaks' gear and all I could get to duplicate were the gloves and boots as well.

I found that leaving the previous armor "in" the mannequin but not equiped, then leaving the cell and coming back helps solve the problem. Sometimes it takes a few tries.