I've set up plenty of Google Analytics cross-domain setups before but for some reason this isn't working in the current scenario:Domains:domain.com.au with UA-XXXXXX-1domain.co.uk with UA-XXXXXX-2The two domains point to the same Wordpress Multi-Site using the WPML plugin setup with separate domains as opposed to sub-domains or sub-folders.Google Analytics (deployed via the same GTM container on both domains) has the following in the general GA Pageview Tag:On domain.com.au:Type: Pageview, Code: UA-XXXXXX-1cookieDomain: autoallowLinker: trueautolinkDomains: domain.co.ukdecorateForms: trueOn domain.co.uk:Type: Pageview, Code: UA-XXXXXX-2cookieDomain: autoallowLinker: trueautolinkDomains: domain.com.audecorateForms: trueBoth Analytics Properties have both themselves and the other domain in their referral exclusion lists.Navigating from one domain to the other has the expected behaviour of appending the _ga=1.... query string but the source/medium information is lost. I tested by naviating to one domain via a google search result (and was shown google/organic as the source medium) but when I switched to the other domain real-time shows me as direct/none. When navigating back to the first domain I again show up as google/organic there.
Wordpress WPML multi-domain Google Analytics Cross-Domain Linking
google analytics;wordpress;google tag manager
After a lot more research and experimentation we've found the following. Cross-domain referral exclusion works only when you are using the same UA code to push to. In other words for one UA that tracks domain.co.uk and one UA code that tracks domain.com.au and then a third UA code that we have come to call Rollup which we push traffic from both domains to.The GA tags in GTM for the Rollup property have the auto-link domains set up for each other and it also has both domains in its own referral exclusion list. This way we can actually see the google / organic as the source/medium when somebody comes from Google, goes to domain.co.uk and then to domain.com.au. That visitor will be listed as google / organic on URL domain.com.au/.....