Calls showing in recent calls which were never made or received

I've searched decently and have been unable to find anyone with this issue.

We have a business account with multiple phones (not all) showing calls on their recents lists which were never made or received. They are all calls from/to people on their contacts list only. They are phones which range from the iPhone 4S to 5/5S to 6. They are running iOS's ranging from 7.x.x to 8.x.x to 9. They do not share iCloud accounts. Some days it never happens, some days show multiple non-calls.

It's an annoying issue, but I'm hoping someone here has seen it and has a solution. Thanks!