1. Set up a vanilla 7.2.x with the latest fix pack and add the following property to your portal-ext.properties file: "layout.first.pageable[url]=true (this allows the first page of a site to be of type "Link to URL).
2. Go to Control Panel --> Sites --> Sites and create a blank site "Test Site".
3. Add a private page to Test Site by going to Site Builder --> Pages --> Add a private page "Page" with the type "Link to Page" then add the following URL: http://localhost:8080/web/guest (this is the default page of the default site).
4. Create a user by going to Control Panel --> Users --> Users and Organizations and add a User then add this user to the created Site by going to "Memberships" and select the Test Site.
5. Go to Users --> Users and Organizations and find the created User and click on the 3 dot menu beside it and select "Impersonate User"
Note: The "doAsUserId" is appended to the URL. Using the profile drop-down in the top right, select "My Sites" and select the "Test Site"
Expected Result: The user is redirected to "/web/guest" with the "doAsUserId" request parameter intact.
Actual Result: the "doAsUserId" is request parameter value is broken, as the parameter and value have been appended to the URL a second time without a separating "&".
7.2.x @ ab8033b0691099263ee598d6d399472cf01e85c5