Added some new users recently who do not have phones. I’m accustomed to adding an AD Attribute to the Proxy Addresses section for the SIP:firstname.lastname@example.org attribute when they have a phone. Because these users don’t, I didn’t.
Apparently, the configuration we have requires this for the Teams Audio Conferencing details to even populate on the user. Without it they can still create and participate in meetings, they just never get the phone number from the audio conferencing assigned.
Once the attribute syncs to Azure AD the audio conferencing info populates right away.