Contacts unlink themselves Lumia 950

Hi. I have a Lumia 950 and every so often, I find that my linked contacts in People become unlinked and I have to go back and link them again. As you can imagine, this is very frustrating. The device backs up regularly on its own and the only guess I have is that when the Facebook app syncs contacts, this may be when it happens. Anyone else experience this issue? Thanks.