In case of multiple hst webapps, only the channels of 1 webapp load correctly in CM

Is a regression, worked fine in CMS 11.

What happens is that in the CM overview, there are three channels: 2 for /site and one for /intranet webapp. When clicking on for example 'English Demo Site', the iframe call that should load the site starts with /intranet but should had been /site (as it was returned by the server for that channel)