Is this a bug in format?

In CMUCL 19c , the expression (format nil "~,2f" 0.0001) returns "0.000".
SBCL returns "0.00" as I'd expect.

cheers,

Alex

;;;;;;;;; CMUCL ;;;;;;;;;;;

>: cmucl
CMU Common Lisp CVS 19c 19c-release + minimal debian patches (19C), running
on pcalex
With core: /usr/lib/cmucl/lisp.core
Dumped on: Mon, 2006-02-20 15:02:51Z on pcalex
For support see http://www.cons.org/cmucl/support.html Send bug reports to
the debian BTS.
or to [email protected]
type (help) for help, (quit) to exit, and (demo) to see the demos

Loaded subsystems:
    Python 1.1, target Intel x86
    CLOS based on Gerd's PCL 2004/04/14 03:32:47
* (format nil "~,2f" 0.0001)

"0.000"
*

;;;;;;;;;;;; SBCL ;;;;;;;;;;;;;;;;

>: sbcl
This is SBCL 0.8.16, an implementation of ANSI Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.

SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses.  See the CREDITS and COPYING files in the
distribution for more information.
* (format nil "~,2f" 0.0001)

"0.00"
*