Is <buffermode>1</buffermode> being ignored in 17b2 and the nightlies since?
There is a long term (since 15) issue with 3 brief pauses over about 5 seconds in flac playback (local, from another drive in the same system) as kodi buffers the next track, usually solved by setting it to cache everything, it is back with a vengeance in 17b2.
Buffermode 1 would completely break music playback in all 17 versions up to b2, would never play the next track and would stop after any single track then not play anything else. Since b2 it plays a queue fine, but the 3 gaps are back.