no whitespace in history

I just tried a recent version of Slime.  When I type
M-P in the slime-repl buffer I see the previous command
I typed, but without any whitespace.  For instance,
"(cons 1 2)" appears as "(cons12)".  In my .emacs file I
have slime-repl-history-trim-whitespaces set to t.  If I set
it to nil, I get the correct history string.  It looks like all
whitespace is being trimmed, not just leading and trailing
spaces.

Emacs 24.3, SBCL 1.1.16.84,

Bob