Are you sure the ProfilePicture object is available? If it hasn’t been created yet, a user can not change it :)
You can fix this by not getting the ProfilePicture object over association, but using a microflow that check if the object is available and if not, create (and link) it to the user
Have you checked the profilePicture entity is being created AND that the the association teamMember_profilePicture is being set before the user reaches the screen?
I ask because if the profile picture object doesn’t exist or can’t be found, then anything inside the profile picture dataview will be non-editable.
I was having this same problem. After seeing Wieke's comment, I fixed the problem this way.
Is the ProfilePicture object created and associated with the Teammember object?