You have seen references from googleads.g.doubleclick.net or tpc.googlesyndication.com traffic from your ads is delivered to AdSense or Google Ads Manager.
Referrals from googleads.g.doubleclick.net are clicks on your ads shown on the Google Display Network, specifically, ads shown on publisher sites in the AdSense program for which destination URLs are not tagged.
Googleads g doubleclick net
If you see googleads.g.doubleclick.net appearing in your reports, check to see that auto-tagging is turned on in your Google Ads account and that your own campaign variables are labeled correctly. went.
https googleads g doubleclick net
Similarly, referrals from tpc.googlesyndication.com result in clicks on ads served on the Google Ad Manager network.