Hello.
I was getting a lot of errno = 24 with my callbacks to open a file from a bank. This error is too manny files opened.
I tracked down, that doing
instance->setTimelinePosition( ... )
especially when seeking time pos in my cutscene editor is making this music instance to invoke HOUNDRETS of new handles to open, literally every time i use this setTimelinePosition - that happens every frame as user drags time marker but never calls CloseCallback. And eventually run out of system limit of avaible file handles 
- Instance is not recreated,
- Open/Close callbacks are done as best practiced suggested. I even tried doing a handle reusage pool, to not open new file every time, but reuse once that were already released.
This is literally blocked for us right now. Do You have any ideas what might be wrong ?
Thanks!