flashing a white screen while open new tab

Hi,
It's nice to know that feature is rolled to the Beta as well, that means it is no longer a controlled roll out feature!

Yes it's happening to Canary and Dev too, I can easily reproduce it by going to my new tab and refresh the page multiple times.
I think at the first millisecond, it loads the white theme New tab page and then it realizes, Oh user is having dark theme enabled, then it loads the dark background version instead.
of course all of these happen in matter of milliseconds or microseconds that's why the end user sees only a flash.

I think the solution would be for the Dev team to prevent Edge from assuming that the default theme is white for everyone, Edge can drop that assumption when the user changes the browser theme in edge://settings/appearance .