Hey! Sorry for the late followup on this, but just as a heads up:
I rigged up debug.ipv4.fly.dev, which runs on every worker node in our fleet, to respond to DNS queries (right now, just uptime.fly. and debug.fly.). So you can get a read on which regions of ours are being routed to:
http://dig.ping.pe/debug.fly.:TXT:debug.ipv4.fly.dev
Something is going on with ping.pe's AMS and our AMS. I’m poking at it, but as you’ll probably see, AMS is reachable from a lot of other places.