Opportunity: Timestamp change of activities after change of owner

Hi to All,

we use Microsoft Dynamics® CRM 2016 (8.0.1.79) (DB 8.0.1.79).

we noticed that the timestamps of all activities which belong to the opportunity change, when the owner is changed. The timestamps all get the timestamp of the change of ownership. We couldn't find any custom code. Is it possible that this is a basic functionality of Dynamics?

Many thanks for your help.

Reibini