I thought my problems went away by clearing the dynamic data. But when I uploaded 1.7 gig of new tracks (very much a rare occasion), it has come back.

The player lags on the silence at the end of a track. Time doesn't count, UI is frozen, button presses are cached and execute 3-5 seconds later when it's done lagging.

I actually think it's lagging on the silence, not while trying to end one track and load the next. I experienced this today with a "secret track"; a single track which has a long pause of silence between two songs. During this silence, the UI was frozen, etc. I think it was still playing because the time increased every 5 seconds or so (I was driving so couldn't really notice). Then it lagged at the end of the next two tracks.

A bad CD? Or a clear case of a symptom I only occasionally saw. Now I've got a track to test it.