BASS_CONFIG_DEV_NONSTOP is disabled by default, so if you aren't changing that setting (via BASS_SetConfig) then that won't be what's causing the problem. But do check whether you're leaving the MIDI stream playing even when it's not playing any events, ie. call BASS_ChannelStop (or BASS_StreamFree) when it isn't in use.
The issue continue happening. BASS_CONFIG_DEV_NONSTOP have not changed, so as you said before, that shoult not be the cause. I have tried to stop all the streams when OnPause, also BASS_Pause (and resuming when onResume), also Bass_Stop() and Bass_Free() and when resuming having to initialize BASS (I know that it is not the best option, since it adds a lot of delay when initializing and loading resources). No much difference in Wake_Locks in all these tests. Around 0,3% of WakeLocks and the maximum value that Google considers acceptable is 0,1%. It is hard to obtain that WakeLock in tests, because it is a very low percenteage. Sometimes, I have noticed that when quitting the app and restarting, some ANR have been issued (and probably this WakeLock), if it is not stopped BASS before, and trying to Init again. I appreciate any kind of help.