PC invisible + muffled but still detected

[Roy192]

There's a Forsworn Briarhearth that keeps killing me with ice storm spells. I tried to sneak to him to steal his hearth but he always detects me when I get close.

I have a pair of dwarven boots of muffling (enchanted those myself so they're 100% effective).
I also have a potion of brief and enduring invisibility which should make me 100% invisible, right?

So sound and vision are out of the question but he still somehow detects me when I'm near. Does he smell me? Or is the invisibility effect capped or something? My sneaking skill is very low but that shouldn't matter...

I looked at my av values and the movementnoisemult is 0 and the invisibility is 1. And I have checked that my follower is waiting somewhere else so that she doesn't give away my position.

 

[EnderEmmy]

Look, broseph. There ain't no cheating your sneaking skill, a higher sneak skill will do the trick, I think it's because of that, the muffling and invisibility only helps a bit, a good sneak skill will help a lot.

 

[Dagmar]

According to UESP, Forsworn are often scripted to have keen hearing. I may took a look at them in the CK later on to verify this but if they're scripts it might mean that they can hear you even while wearing 100% Muffle enchanted boots.

 

[Nakatsu_Hime]

Perhaps you're just naturally clumsy.

 

[berzum]

perhaops they can smell you lol all joking aside raise your sneak lvl and it'll be a piece of cake