Thanks Sven, just wanted to make sure I wasn't missing anything obvious since I know it was working before. I've voted for all the uservoices that look like they might apply, and I know changes are coming. But I have a CEO that wants something now! :)
It's making it difficult to test how meetings work when the presenter is a guest - I can test it from my MacBook Pro but that throws mac related issues into the mix.
@svenseidenberg Closing off this message as Teams version 19260 just downloaded for me and this issue is fixed!
On my work computer, I can now sign in to Teams with my private business account, see my business tenant, then use the tenant link next to my profile to switch over to my work tenant as a guest (biz email is guest tenant). (Before it would switch over to the work tenant, show briefly, then put me back into my work tenant).