Teams Live Events - any changes since Nov 2020 that impact Cross-Tenant permissions for Live Events?

Some time after November 2020, we noticed that certain types of cross-tenants guests (namely those on MS 365 Businesss plans and Teams Free accounts) can not join reliably as Producers in Teams Live Events that I create (I am on a E3/E5 licence), whereas Enterprise Users still seem to be able to particpate as Producers. In test Live Events, when the non-Enterprise user clicks "Join Live Event" (invited as a Producer or Presenter) they instead only enter the meeting as an Attendee.

Initial Testing

I've done some reasonably rigourous testing since experiencing initial problems. To do so, I created two test Team Free accounts, testoutlook@outlook.com and the other at testyandex@yandex.com (verified as primary alias for a hotmail.com address) on a second machine. I validated both of the accounts and signed-up for Teams Free (which seems to be needed in addition to the MS accounts alone). From my first machine (the Live Event host on E3 licence), I added both test users to a Team (required by MS for guest accounts/participation), created five Live Events and invited each of these accounts in various roles - Producer and Presenters. In my experiments I tried different things, such as:

• accepting or not accepting the invited users (on second machine)

• signing into Teams app first, or signing out before "Join[ing] Live Event"

• having the test guest account join after the host and before

• launching the meeting on the test accounts

• rebooting the second machine between test meetings to clear cache

Initial Observations

What I can tell you is that there were no clear patterns in the results, as follows:

• sometimes the test accounts signed-in as Producer when invited as Producer

• sometimes the test account would sign-in as a Presenter when invited as a Producer

• sometimes the test accounts would sign-in as Attendee when invited as either Prod/Present

• sometimes the test accounts would sign-into the meeitng as Producer but show in Presenter

• sometimes the Teams app on the guest test machine would prompt for "Which group?"

• sometimes the Teams app would "run into problems" ("collecting info")

• somes the Teams app would fail to load

Initial conclusions

None of the testing demonstrated any repeatability and as such I have absolutely NO confidence in my ability to succesfully run a meeting with five presenters on Tuesday (two of which are Teams Free users) and 150 attendees.

Further testing

I just held a test meeting with two real humans (one on a MS 365 Business Plan and one a Teams Free user). What we discovered out of that event was that if the MS 365 Business Plan user joins the Live Event from his Teams Calendar using "Join Live Event", he gets kicked to Attendee only, but if he joins using "Join Live Event" from his Outlook Calendar, he correctly connects as Producer. I had them both rejoin four times and this behaviour was repeated - however, I know that doesn't gel with my testaccount experience above perfectly - so far, this is a working theory.

Have there been any changes to Teams permissions that would negatively impact rights of Cross-Tenant Producers in Live Events?

If anyone is willing, I am happy to add you to my Team and set up a test Live Event.