I don't own an XP-60 but I've heard about
several other XP-60 complaining
about that bug. Try out
rec.music.makers.synths. There's a
whole discussion about that topic here.
Just DON'T give Roland the benefit of the
doubt. You'll be a very sad consumer 'cause
they won't even try to solve your problem.
I'm having the same problem with my JX-305
at the moment.

My advice : take your gear back to the shop, and be sure to have a lot of information about possible bugs before you buy any other synth.