[Android] Audio lost unless endCall is forced, and lockscreen accept doesn’t launch app

Description

I am using react-native-callkeep together with jssip, react-native-webrtc, and react-native-incall-manager to build a SIP calling application.
On iOS the integration works fine, but on Android I am running into two major issues:

1. Audio Lost unless I call endCall on answer event

• When I answer a call, audio only flows if I explicitly call endCall(callUUID) inside the answerCall handler.
• On iOS, I don’t need to do this extra endCall and audio works normally.
• This feels like an inconsistency or unintended behavior.
• If endCall is the only solution to make audio work, then on Android it seems CallKeep is only acting as a UI layer, not actually maintaining the call session, which makes its role different from iOS.

2. Lock Screen Call Connect Limitation

• When receiving a call on the Android lock screen, the CallKeep UI shows up.
• If I tap Accept, the call does not actually connect to my app until I unlock the device.
• On iOS, accepting the call from the lock screen launches the app in background and immediately connects the session (expected behavior).
• On Android, I need to manually unlock the phone before the call session actually connects, which is breaking the user flow.

Environment

• React Native version: 0.78.3

• react-native-callkeep version: 4.3.16

• jssip (handles SIP signaling)

• react-native-webrtc (media streams)

• react-native-incall-manager (audio routing)

• Notifications:

  • Android: Firebase push notifications
  • iOS: VoIP push notifications (PushKit)

• Platforms affected: Android only (iOS works as expected)

Additional Notes

• My goal is to use CallKeep consistently on both iOS and Android.
• I want to avoid hacks like calling endCall immediately on answer, since that breaks the call lifecycle logic and makes Android behavior diverge from iOS.
• Ideally, accepting a call from the lock screen should:
  • Launch the React Native app in the background automatically (like iOS does).
  • Initialize the SIP session (via JsSIP + WebRTC) without requiring the user to unlock the device.
  • Maintain audio without calling endCall explicitly.

Any guidance on correct integration patterns, workarounds, or whether this is a limitation in Android’s ConnectionService would be highly appreciated.

The report names no source files, tests, or entry points. Start by reproducing Android answer handling and lock-screen acceptance with the stated React Native 0.78.3 and CallKeep 4.3.16 setup; determine whether audio and background app launch are supported or platform-limited, then document a confirmed integration path or limitation.