I get the "no names" from the PersonMetadata group, however this only became a problem after my account was migrated to Office 365, this also happened to my father who has a Samsung alpha phone. he got around 500 "no name" entries and he only had 54 contacts
originally. I've seen at least one other post for the "no names" problem and it seems to come from the outlook account. I've found it seems to come from the outlook migration.
He then seemed to have multiple entries for his contacts once we had cleared up the "no names" entries. So I removed the email account from his phone deleted all contacts on the phone, cleaned up the Microsoft "People" app and re added the email account.
There were still several multiple entries.
Trying to get to the bottom of it now.