We're sorry that you're running into this and are working on getting this fixed. It is a known issue, so in the interim, please just move navigate back to the legacy UI. Watch this community for an update!
How do you get to the legacy UI?
The official answer, @brianwaugh:
If an issue is encountered where there is a need to switch back to the legacy UI, we strongly encourage you to file a support ticket, so that we can provide assistance with resolving the issue.
Unofficially, we will be watching closely to see what advantage the legacy UI still offers.