Playback quality differs between 1st and 2nd time on repeat

This is reproducible for me (MuseScore 1.1, Vista), but subtle. With the following score loaded, using the default "TimGM6mb" soundfont and playback set to swing, I get reasonably legato playback from the woodwinds at first, even though I have no slur markings added (and as far as I know, those have no playback effect whatsoever). But on the second time through on the repeat, the woodwinds are noticeably less legato. Actually, the playback the second time is about what I'd expect in the absence of a slur marking; the playback the first time is closer to what I'd expect if there were slurs. So I'd almost say, whatever is going on here, consider using it as an implementation of slur playback!