Pause and Rewind problems

[screenclene]

Recently I've been having problems with pausing long (30 min) mp3 files.
I have a the rewind on pause option set to 5s. This has worked well for ages on Mono CBR mp3 files.

Now I have switched to stereo files: 64kbps, CBR, mp3 format.  The rewind on pause feature has become very unreliable, skipping backwards up to a couple of minutes instead of just 5s when I resume play.

Resuming files from Bookmarks still works perfectly on the same files, with the rewind feature working there as it always has, but rewind from pause is now pretty bad.

Is there a ways to fix this?
Should I encode my mp3 files to a different format?