Self-referrals in Google Analytics are caused by improper cross domain tracking often caused by using a tool or platform which links to a different root level domain from your site where you want to maintain tracking.
The “allow linker” plugin does not always fix cross domain tracking problems as it only looks for HTML links within the page code to attach cookie data. Forms, single sign on solutions or widgets can use javascript to direct the user to another domain where tracking can be maintained. In this case custom scripts have to be developed to pass the cookie data through the forms.
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