Sound warnings in console

Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_1137801172_1964887113' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_1137801172_1964887113' not found in method 'play'
Client> [20:48:29] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:48:32] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:01] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:03] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:12] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:20] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:28] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:37] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:41] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:44] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:51] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [20:49:59] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none

Client> [22:10:44] [Server thread/INFO]: Saving chunks for level 'MojiraTest_1.7'/The End
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_144744200_1482115154' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-8433035_248048112' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-1111042530_91685791' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-921390258_1493747516' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_144744200_1482115154' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-8433035_248048112' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-1111042530_91685791' not found in method 'play'
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Source 'Source_-921390258_1493747516' not found in method 'play'
Client> [22:30:04] [Client thread/WARN]: Unable to play unknown soundEvent: minecraft:none
Client> [22:30:27] [Server thread/INFO]: Saving and pausing game...