Safari keeps on opening itself

HI,

Since the las 24h in my 2018 15" Macbook Pro Safari keeps on opening by itself. The Safari window does not pop up but this icon appears on the Dock:

If I click on it it always opens up with the same page I am seeing through Chrome on my Mac Mini M1. Also, the strange Safari Icon reappears on the Dock every time I open a new tab on the Mini's Chrome browser. I've had these two computers working since I got the Mini M1 2 months ago and never happened before. Much less with my older Mac Pro. I've deactivated extensions but no go. I have not updated anything in the past 72h so I'm confused. My guess is that it has something to do with my Apple ID but I don't have a clue about why.

Does anyone know why this happens "all of a sudden"?