Outlook App opening a browser Tab

Sorry I thought my reply picked up the picture comment I was replying to but I now see I didn't tick the box!
It's a setting in Edge; I still use Brave as the default browser, I didn't change that.

I opened Edge and went to the settings within Edge not the PC settings:

settings/system & performance/Continue running background extensions and apps when Microsoft Edge is closed (it's near the top) - I switched this off and it worked for me. I didn't have to fiddle with the calendar or teams settings at all.

Screenshot of the reply that fixed it for me:

Thanks for clarifying and for the screenshot! Unfortunately, this doesn't work for me.

and this morning I have just discovered it does not now work for me either!

I have just launched Outlook and a new tab opened with the envelope logo. The setting in Edge is still off.

Ugh, this is rubbish.

The good news is, they're working on it! Several posts up, someone reported the link that MS is aware of the issue and plan to have a fix in April. I glanced through it and I believe it mentions the calendar issue but it doesn't mention the startup issue. Since they both produce the same result (the browser opening), lets hope they fix both at the same time!