Ok so this was posted on the issue forums but doesn't seem like anyone goes there

There will be a spoiler on one certain glove, so please don't read this if you don't want it spoiled.

Well the normal shrouded armor description is only backstabs, although I get them on all one handed sneak attacks.
Ancient shrouded armor description is every 1h weapon gets double, again I get them on all one handed sneak attacks.

You have the perk in sneak that gives you 15x in the first place, right? And you are using a dagger?

Yeah i have the x15 perk and daggers. But it still doesn't work =/

I've found that sometimes enchants don't register. Re-equipping the item rectifies the issue.

Ah ok, i'll try that .

Edit :

Yepp it worked! Kudos Tale, owe you one.