I too am unable to see the broadcaster views when in hosted testing. Viewer view works fine. Configuration was not working straight away but then started to work. I notice i get the following error in the log although not 100% sure it is it.
Refused to display ‘https://supervisor.ext-twitch.tv/supervisor/v1/index.html?language=en&mode=dashboard’ in a frame because an ancestor violates the following Content Security Policy directive: “frame-ancestors https://.twitch.tv https://.twitch.tech https://localhost.twitch.tv:* http://localhost.rig.twitch.tv:*”.
This is with Hosted Test, Testing (Localhost) works fine although i remember they said you had to add localhost.rig.twitch.tv for the new development rig setup but this should be after that anyway.
Whats strange is the viewer comes from:
https://5ul5ajg49sjyrc8ezab5qqv25fdscp.ext-twitch.tv/5ul5ajg49sjyrc8ezab5qqv25fdscp/0.1.1/d4d2fe430134f940b4ad4a89f4ac5c6f/viewer.html?anchor=panel&language=en&mode=viewer&state=hosted_test&platform=web