Preview tabs unmerge after a restart


If I have a Preview window with multiple tabs inside, then after I restart my mac (Catalina version 10.15.7), all the tabs “unmerge” into their own separate windows.

Is there a way to stop this from happening?

I know how to merge all Preview windows into one window composed of multiple tabs. This is not ideal because sometimes I want to have certain windows kept separate and it is quite annoying to have to manually redo this after every restart.