If your connection is stable, there should be no problems with using FLAC. I've added FLAC buffering issue to bug tracker, if there's a bug, will be fixed in one of the next updates.
Hello Dmitry, is a solution to this problem possible in the near future?
Now we have a dedicated internet link to send Flac audio. However RB continues to have problems every two to three hours. (I think internally it uses less than 5 seconds of buffer when using flac).
We tried another player with 10 seconds of buffer and the playback is totally stable.