Collective.smsauthenticator not always delivering Twilio SMSs

Recently I noticed that Twilio SMSs are not arriving reliably to mobile numbers that have had no trouble receiving the same in the past.

Have any of you using this add-on noticed similar non-delivery recently? (past month or so)

The Twilio docs show that webhooks can be used to provide delivery status for a message. Is there a way to get delivery status that does not require setting up another listening process?

It looks like the message delivery errors ("(Error: 30034) US A2P 10DLC - Message from an Unregistered Number") are related to this