I'm having the same problem too!!! I actually thought it was part of the mask until I saw my chin poking out of the mask so my immersion has been broken lol. I really hope ZOS fixes this soon because this is a really cool mask.
So far I have test on all my characters. This bug seems to ONLY affect Male Dunmer's faces. I will say though I have no Bretons or Imperials. If you have those characters in male and female, can you guys see if the mask clips in the nose, lips and chin? Obviously only is you have the mask. But even my female Dunmer doesn't clip at all like this. I have 2 male Dunmer, they both clip through nose, lips and chin. @ZOS_GinaBruno I have sent a bug report but can you see if this is being looked into?
Please and thank you