Safari in Sonoma opening my Work profile when I focus back to Safari

In Safari, I've set two profiles: Personal (the default) and Work. My Work profile suddenly opens when I switch to Safari from another app, even if I was browsing with the Personal profile.

I can reproduce it:

1. I open Safari with a Personal profile window to any website
2. I switch to another app (e.g. with Cmd+Tab)
3. I switch back to safari: a new Work profile window opens.

This is annoying because I expect to focus to the website I was browsing before, while instead I see the home page of another profile.

What should I do to stop the Work profile opening when switching back to safari?