I always thought that these outages were relatively benign from a user perspective, but after the last major WhatsApp outage a few weeks back I somehow got logged out of my main phone as I tried to "log in" to my 2nd device (and later failed to log back in to the main device that has all data). It appears such edge cases aren't really thoroughly tested, which seems disappointing but also surprising to me.

I'm still seeing the normal AS714 prefixes in my table, both over direct IX peering sessions and via transit. If it's BGP, it's not an issue with their external announcements.

It’s always BGP!