iOS 26 screen sharing via FaceTime doesn't display incoming calls from a third iPhone

Start a FaceTime Audio call between two iPhones, then start screen sharing from one to the other, and finally start remote control. The iPhone being controlled needs to be upgraded to iOS 26.

While sharing the screen via FaceTime Audio, use a third phone (it doesn't have to be an iPhone) to make a regular phone call to the iPhone being controlled.

The bug is that the controlled iPhone doesn't display this incoming call, whereas it did under iOS 18.

Details: the controlled iPhone just pops up its Dynamic Island, showing the contact name of the controlling iPhone instead of displaying the incoming call from the third phone as expected. Moreover, a red dot appears on the Phone app icon, and a new missed call record appears inside the Phone app. Meanwhile, on the third phone, the call is still active and waiting for an answer, not disconnected.

[Re-Titled by Moderator]

Original Title: On iOS 26, when sharing the screen via FaceTime, an incoming call from a third cell phone isn't displayed