Hello Petersen,
* I am a Microsoft user like you, providing solutions to community members; I am NOT a Microsoft employee.
The fact that you see a random 12-digit number instead of the caller ID when using Teams phone connected to your car via Bluetooth points to a compatibility issue between Teams and your car's infotainment system. Here are some possible solutions:
Check for Teams Updates: Microsoft regularly releases updates that include bug fixes and compatibility improvements. Make sure you and your colleagues are all using the latest version of the Teams app.
Contact Microsoft Support: If you're using the latest version of Teams and the issue persists, it might be a known issue with a fix in the works. In fact, I believe that this is the case; since caller ID features are a bit limited in Teams at the moment.
Here's a thread, where another Independent Advisor addresses a similar issue:
https://answers.microsoft.com/thread/3ad7df41-3d78-49cd-9f93-791fed4482be#:~:text=Hi%20Dominik%2C-,I%20understand,-that%20you%20want
My suggestion is the same as his,
"... allow me to share this channel where all the feedbacks are posted. This might already be shared by others but if not, you may submit this as a fresh idea. Please make sure to upvote those feedback that you think would make the app better for a higher chance of them to be implemented in the future updates.
https://feedbackportal.microsoft.com/feedback/forum/ad198462-1c1c-ec11-b6e7-0022481f8472"