More People in "Teams/Organisation" than in Delve / Active Directory

Hi, 

we have the following problem. There are 4 people, that are "Guests" in our Teams, that appear in the organisation of one of our employees.
They are no members of our structure in the active directory and you can't see them in the "delve" organisation.

How could I "cut the connection" in the organisation tab to this guests? How did they appear there?

Greetings

Annette