Nope.

Yes, it is black when I turn "Dark Mode" on. 

It's white for me (with content, not just a blank page) whether I'm in light or dark mode, in Firefox. I've noticed that Google seems to be very buggy with its dark mode implementation, as in the past I've had it flip from one to the other as I work my way through the results.

Hmmm, I turned Dark Mode off yet middle rectangle stays black.  Only happened after some updates this morning.

And now mine's gone black. I'm in light mode.

     >And now mine's gone black. I'm in light mode.<

It wasn't me, promise 😆

There is apparently a global issue with youtube - could be related?

UPDATE:  Found that clearing Edge cache/history fixed the issue.