This looks more like a glitch than a phish.
The messages I receive come from 78156. Here's an example:
"<#> Your Airbnb verification code is: nnnn. Don't share this code with anyone; our employees will never ask for the code. qkpTe1dy0zl"
Why it starts with "<#>" and ends with "qkpTe1dy0zl" is a mystery.
Replying HELP to the message returns:
AuthyMSG: To learn why you got this message, please visit https://twil.io/why-verification. Reply STOP to stop texts. Std Msg/data rates may apply.
That link is not a phish. Twilio is the service Airbnb uses to send verification codes when you attempt to login to Airbnb on a new device. Going to that link essentially tells you that the message comes from a company that uses their service and replying STOP may break your ability to get valid authorization messages when you do sign in on a new device (or one where you've cleared cookies).
I just cleared cookies for airbnb.com to simulate signing onto a new device and Airbnb sent a verification code message from 78156 that is identical to the mystery messages except that it doesn't have the weird prefix and suffix text noted above.
Maybe these messages are a result of hackers trying to login to Airbnb accounts, but why the strange prefix and suffix text on the messages? Anyhow, I wish Airbnb would look into this and let us know what they find.