Yes it happens to me. To explain my bug(I don't know if it's an intended feature or bug), but consider I have 1 window of safari and 10 tabs in it. Then I open a new tab, open netflix in it and pull it out to make a new window. Now, a proxy or duplicate of netflix is opening in the main window(along with my other 10 tabs in it) and this netflix in my second window is somehow being synchronized with the one opened in the first window(like in the image I attached). So when I close the one in second window, it's proxy is also getting closed or vice versa, if I close the proxy, the tab in second window is also being closed! It's annoying!!! I didn't find any option to not have this feature, so I don't know if this is a bug or a feature, but seriously it's annoying!!!