It looks like Google notifications are using mtalk.Google now instead of firebaseinstallations.googleapis and fir-auth-gms.firebaseapp
I was messing with my DNS settings the other day and noticed mtalk.google coming from my phone and hadn’t seen that domain before. Figuring it was a new google tracking domain, I blocked it. Flash forward three days and I haven’t been getting notifications properly, remove the block and get a ton of missed messages and alerts coming through. Figured I’d post here in case anyone else is having an issue or wondering what the domain is doing.
P.S. MySudo seems to send but not receive any messages if this domain is blocked, they sit waiting for it to be open again and then all come in at once.