Same is happening with me for iOS 12.2. but it's running fine on iOS 14.3.
2020-12-30 13:01:45.440466+0530 Easy Meditation[8040:217664] [AudioHAL_Client] HALB_IOBufferManager.cpp:226:GetIOBuffer: HALB_IOBufferManager::GetIOBuffer: the stream index is out of range
2020-12-30 13:01:45.460926+0530 Easy Meditation[8040:217664] [aqme] 254: AQDefaultDevice (1): output stream 0: null buffer
2020-12-30 13:01:45.461163+0530 Easy Meditation[8040:217664] [aqme] 1640: EXCEPTION thrown (-50): -
2020-12-30 13:02:00.410118+0530 Easy Meditation[8040:217375] [aqme] 177: timed out after 15.000s (0 1); suspension count=0 (IOSuspensions: )
2020-12-30 13:02:00.412395+0530 Easy Meditation[8040:217375] 239: CA_UISoundClientBase::StartPlaying: AddRunningClient failed (status = -66681).
2020-12-30 13:02:00.493511+0530 Easy Meditation[8040:217900] [AudioHAL_Client] HALB_IOBufferManager.cpp:226:GetIOBuffer: HALB_IOBufferManager::GetIOBuffer: the stream index is out of range
2020-12-30 13:02:00.493689+0530 Easy Meditation[8040:217900] [AudioHAL_Client] HALB_IOBufferManager.cpp:226:GetIOBuffer: HALB_IOBufferManager::GetIOBuffer: the stream index is out of range
2020-12-30 13:02:00.505923+0530 Easy Meditation[8040:217900] [aqme] 254: AQDefaultDevice (1): output stream 0: null buffer
2020-12-30 13:02:00.506240+0530 Easy Meditation[8040:217900] [aqme] 1640: EXCEPTION thrown (-50): -
2020-12-30 13:02:15.458469+0530 Easy Meditation[8040:217895] [aqme] 177: timed out after 15.000s (1 2); suspension count=0 (IOSuspensions: )