From the 11:06:31 PM UTC update:
Current status: We've begun returning a portion of the affected servers to service, and they're remaining stable so far. We've also shifted traffic and connections to alternative pathways wherever possible and have observed limited recovery in some regions.
We've streamlined our recovery process to expedite returning the remaining affected servers to service. To further support recovery, we're implementing protective traffic management measures in a specific location to reduce load on the affected infrastructure, and we'll expand these measures to additional locations if we observe positive results. As capacity is restored, users may experience a gradual recovery as their clients reconnect to the service.
Reddit-level speculation.