iOS: When Bluetooth device is available, incoming call defaults to receiver/earpiece when answered

Bug report

• I've checked the example to reproduce the issue.

• Reproduced on:

• Android

• iOS

Description

When a BT device is connected, outbound calls will automatically connect to the BT audio route.

But for inbound calls, the audio gets routed to the receiver/earpiece instead of BT.

When I print out the events for RNCallKeepDidChangeAudioRoute, I receive a bunch of them once I answer the call. Sometimes they start off as BT, but it gets overrode by subsequent events showing receiver as the audio route. These events are triggered outside of my app.

Steps to Reproduce

Connect your device to BT device. Place an inbound call to CallKit app. Answer the call. Notice the audio route is not BT.

Versions

- Callkeep: 4.3.3
- React Native: 0.66.3
- iOS: 15.4.1
- Android: N/A
- Phone model: iPhone 11

Logs

Paste here

Start with the linked example and reproduce the inbound-call flow using a connected Bluetooth device on iOS. Observe the RNCallKeepDidChangeAudioRoute events after answering and compare them with the outbound-call behavior. Done means inbound calls retain the Bluetooth audio route instead of ending on the receiver/earpiece.