Avatar disappears at all after editing of hidden textbox with avatar's data in Profile page

Steps:

1. Go to user's profile on Profile page
2. Display hidden elements (for example: use Web Developer - add-on of Firefox)
3. Edit data in textbox with avatar data
4. Save profile

AR: Current avatar is removed. There is no avatar in avatarbox at all.
ER: Avatar data restores to devault value after saving of profile (default avatar is in avatarbox after saving of profile)

If user clicks on remove avatar button and save profile - default avatar is appeared