Tesla app notification on iPhone and watch

No one from Apple will respond to this post. This is a user to user support forum and Apple does not participate here.

I would suggest a test and put your phone in the car again like it was, then go back into the house where you were. Then look at the Watch and press the power button on the Watch to bring up the control center. Look up at the top and see if the Watch and iPhone are connected. If they are connected, you will see the green phone icon. If not, I believe it was a red icon with line through it. While the Watch and phone can both use BT, wi-fi, and cellular, for notifications, my understanding is BT, and that is short range.

If you wish to verify this with Apple, you can use the Support link at the top or bottom of the page here, or if you have an Apple Store close by, stop in and speak to someone.

My thought is that the iPhone was out of range from the Watch. It communicates via Bluetooth. The notification from the app is shared via BT, not wi-fi.