1) The title of the tune I was listening to was 'I Could Have Lied - Red Hot Chili Peppers', so No, I don't believe it's complaining about bad headers.
2) The files have played just fine on XMMS, etc, and other versions of the player software, and has played correctly several times since this happened.
3) I didn't try the front panel buttons during all three instances I observed (it could have happened while I was in another room, as well).
4) Isn't it true that the player software does the nifty 'transient titles at the bottom' stuff? It's a little fuzzy on just how Mlord's work would interfere with that, but I suppose it's possible (Murphy's law and all).

In short, it was something which was unusual, and figured that I'd check to see if someone else had also seen this happen before I go and file an official bug report.