Why are utm parameters removed and gad_source=1 added instead

We have Google Adwords campaigns with our utm parameters. UTM paramters are somehow passed, because I can see campaign names and keywords in the menu “acquisition/campaigns”.
however, when I check the visitor log, then I never see the complere URL. All UTM paramters are removed and insted it shows /mypage/gad_source=1
I searched help and forum, but could not find anything.
Does anybody know why this happens?
And is there a way somehow to retrieve the full URL? Because even in the database in matomo_log_visit is not the full URL