AudioMixerSourceManager Crash and Log Spam

@dan.reynolds I am sitting at version 25.3 and am experiencing following crash related to audio mixer. The crash occurs on cooked and packged build in Development Configuration. After checking log file I see following errors:



[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: Ensure condition failed: MixerSources[SourceId] == nullptr [File:D:/Build/++UE4+Licensee/Sync/Engine/Source/Runtime/AudioMixer/Private/AudioMixerSourceManager.cpp] [Line: 787]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error:
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: Stack:
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x000000014622feb7 tbd.exe!DispatchCheckVerify<bool,<lambda_fa063c4b1d37e791afab14ea142e4c06> >() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a66e48 tbd.exe!FSubmixEffectSubmixEQSettings::operator=() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a98dcc tbd.exe!Audio::FMixerSourceManager::PumpCommandQueue() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a75209 tbd.exe!Audio::FMixerSourceManager::ComputeNextBlockOfSamples() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a94a1c tbd.exe!Audio::FMixerDevice::OnProcessAudioStream() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a4ed5c tbd.exe!Audio::FOutputBuffer::MixNextBuffer() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a4fa3c tbd.exe!Audio::IAudioMixerPlatformInterface::RunInternal() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000143a4f89e tbd.exe!Audio::IAudioMixerPlatformInterface::Run() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x000000014173c5df tbd.exe!FRunnableThreadWin::Run() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000141733700 tbd.exe!FRunnableThreadWin::GuardedRun() ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000076b9652d kernel32.dll!UnknownFunction ]
[2020.09.30-11.23.18:341][925]LogOutputDevice: Error: [Callstack] 0x0000000076dcc521 ntdll.dll!UnknownFunction ]


then it hits another ensure:



[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: Ensure condition failed: SourceInfo.SubmixSends.Num() == 0 [File:D:/Build/++UE4+Licensee/Sync/Engine/Source/Runtime/AudioMixer/Private/AudioMixerSourceManager.cpp] [Line: 792]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error:
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: Stack:
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x000000014622dd77 tbd.exe!DispatchCheckVerify<bool,<lambda_fa063c4b1d37e791afab14ea142e4c06> >() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a66eb5 tbd.exe!FSubmixEffectSubmixEQSettings::operator=() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a98dcc tbd.exe!Audio::FMixerSourceManager::PumpCommandQueue() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a75209 tbd.exe!Audio::FMixerSourceManager::ComputeNextBlockOfSamples() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a94a1c tbd.exe!Audio::FMixerDevice::OnProcessAudioStream() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4ed5c tbd.exe!Audio::FOutputBuffer::MixNextBuffer() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4fa3c tbd.exe!Audio::IAudioMixerPlatformInterface::RunInternal() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4f89e tbd.exe!Audio::IAudioMixerPlatformInterface::Run() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x000000014173c5df tbd.exe!FRunnableThreadWin::Run() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000141733700 tbd.exe!FRunnableThreadWin::GuardedRun() ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000076b9652d kernel32.dll!UnknownFunction ]
[2020.09.30-11.23.24:116][926]LogOutputDevice: Error: [Callstack] 0x0000000076dcc521 ntdll.dll!UnknownFunction ]


and the last one:



[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: Ensure condition failed: SourceInfo.DebugName.IsEmpty() [File:D:/Build/++UE4+Licensee/Sync/Engine/Source/Runtime/AudioMixer/Private/AudioMixerSourceManager.cpp] [Line: 862]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error:
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: Stack:
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x000000014622fd67 tbd.exe!DispatchCheckVerify<bool,<lambda_fa063c4b1d37e791afab14ea142e4c06> >() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a677ae tbd.exe!FSubmixEffectSubmixEQSettings::operator=() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a98dcc tbd.exe!Audio::FMixerSourceManager::PumpCommandQueue() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a75209 tbd.exe!Audio::FMixerSourceManager::ComputeNextBlockOfSamples() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a94a1c tbd.exe!Audio::FMixerDevice::OnProcessAudioStream() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4ed5c tbd.exe!Audio::FOutputBuffer::MixNextBuffer() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4fa3c tbd.exe!Audio::IAudioMixerPlatformInterface::RunInternal() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000143a4f89e tbd.exe!Audio::IAudioMixerPlatformInterface::Run() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x000000014173c5df tbd.exe!FRunnableThreadWin::Run() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000141733700 tbd.exe!FRunnableThreadWin::GuardedRun() ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000076b9652d kernel32.dll!UnknownFunction ]
[2020.09.30-11.23.24:117][926]LogOutputDevice: Error: [Callstack] 0x0000000076dcc521 ntdll.dll!UnknownFunction ]


Finally it spams with bunch of repeating messages:



[2020.09.30-11.23.42:722][418]LogTemp: Resetting audio stream to device id
[2020.09.30-11.23.42:755][419]LogAudioMixer: Display: 0: FrontLeft
[2020.09.30-11.23.42:755][419]LogAudioMixer: Display: 1: FrontRight


and then the log file ends.

Is this crash anyhow related to the one from the begining of this thread? Is there a way to fix this without modifying engine code?

Can you describe what is happening when this crash occurs?

It looks like an invalid MixerSource ID.

@dan.reynolds game usually drops in frames, so it looks like it struggle with something for a second or two. Then it crashes. I cannot really find anything that could help finding reproduction steps unfortunately.