I am having following after upgrading to iOS 12 & XCode 10:
2018-09-20 11:58:09.622656+0400 MyApp-Swift[1027:137400] [avas] AVAudioSessionPortImpl.mm:56:ValidateRequiredFields: Unknown selected data source for Port Speaker (type: Speaker)
Any idea what it is, is it a bug in app or known issue in iOS 12?