BTW
I turned on bluetooth debug and checked the logs.
And as I see, everything fine with my headphones, system receives play, forward, backward key presses, but do nothing with this.
21:30:06.449536 +0300 bluetoothaudiod MDR-1ABT has protocol A2DP in state Connected (pending:None)
21:30:06.449573 +0300 bluetoothaudiod [Suspend Complete] returning: 0x0
21:30:18.029536 +0300 bluetoothaudiod Get Play Status
21:30:18.096836 +0300 bluetoothaudiod Play
21:30:18.096892 +0300 bluetoothaudiod Signpost 1 AVRCP Play
21:30:18.103353 +0300 bluetoothaudiod Play Release
21:30:21.295900 +0300 bluetoothaudiod Forward
21:30:21.303052 +0300 bluetoothaudiod Forward Release
21:30:23.345843 +0300 bluetoothaudiod Backward
21:30:23.353210 +0300 bluetoothaudiod Backward Release
21:31:16.529983 +0300 bluetoothaudiod Get Play Status
21:31:16.606279 +0300 bluetoothaudiod Play
21:31:16.606370 +0300 bluetoothaudiod Signpost 1 AVRCP Play
21:31:16.649665 +0300 bluetoothaudiod Play Release
21:45:58.538167 +0300 bluetoothaudiod Get Play Status
21:45:58.606766 +0300 bluetoothaudiod Play
21:45:58.606823 +0300 bluetoothaudiod Signpost 1 AVRCP Play
21:45:58.607396 +0300 mediaremoted Received command from client : , destination app = (null), remote control interface = (null), options = { kMRMediaRemoteOptionSendOptionsNumber = 0;}>21:45:58.607515 +0300 mediaremoted No context for context-sensitive command , destination app = (null), remote control interface = (null), options = { kMRMediaRemoteOptionSendOptionsNumber = 0;}>21:45:58.612993 +0300 bluetoothaudiod Play Release