Microsoft Teams Broken with Latest Safari Update

After my update to Monterey 12.3 last night, I notice now that when in Office 365 Outlook in Safari, that when I click on a Microsoft Teams Join button in O365 that it takes me to the usual webpage, but now the option to use the Teams App is unclickable.

I've since disabled the "Enable contents blocker" for the page in Safari, I've also cleared all cache, I've removed Teams and and ~Library directories associated with it, I've reinstalled it, but still it will not open.

It all works okay in Firefox, so I can only assume Apple have been a bit overzealous in locking down against malware exposure in Safari without whitelisting trusted applications or providing info on a workaround.

For now, I need to bin Safari for Firefox, but hoping someone can help me in how you you can open an MTS stream through Safari to spawn the Teams application.