Michael,

Is the seat (leather) sagging? I can't imagine what would
cause the saddle to go south all of a sudden.
New shorts?
change in saddle position?
whenever something like this happens to me (not sore
nads or anything) I always have to ask What changed?

You could send e-mail to Bill at Wallingford bikes he
seems to be the Brooks expert to end all.

Marty