OneDrive “Share” window stuck loading from File Explorer (works on web)

We are also getting this. The New share method works for the first few minutes after a reboot, then the old share method pops up and donuts forever. We can also close OneDrive and it defaults back to the new Share UI. A Trace showed it dieing in wintypes.dll and just waitng forever for an answer. Key here: The new UI seems to default back to the old one when it can't get a login/token of some kind, that's the donut. Sometimes you get lucky and the NEW UI crashes out with "Your cloud account could not be loaded" (German original: Ihr Cloudkonto konnte nicht geladen werden.") which seems to me to point more at the issue. I am GUESSING the new update removed a function somewhere and noone told the Win.Explorer developers..