Cross webapp links broken in Channel Mgr

Reproduction:

1) Make sure to have two HST site webapps
2) Create an internal document link between documents A and B where A belongs to a site in webapp 1 and B to a site in webapp 2
3) Open the channel mgr one of the sites (and do not yet open the other site in the channel mgr, thus not yet an SSO handshake has been done for that webapp!)
4) Go the page for the document A, and see the cross webapp link in the document. The link doesn't work

Cross site webapp in Channel Manager website links do not work IF the ‘sso’ handshake did not yet take place for the webapp to which the link points, and also it will not even work after the handshake IF the target site webapp has a different domain than the current site webapp (which for the BRC test env by coincidence happens to be so but for customers typically not).

It seems the HST creates the wrong URL: It should include something like ?org.hippoecm.hst.container.render_host=xyz in a URL, but it doesn’t.

The above is an annoying bug which is also hard to test with BRC because in that setup in general we have both site webapps being accessed by the same HOST NAME (resulting in same 'render host'.