Barton, I'm guessing something got broken recently (around Dec 6). I have builds dated Dec 5 w/ cvs Maxima + GCL and SBCL, and those do not show the bug. But builds dated Dec 7 w/ CMUCL and Clisp, and Dec 12 w/ ECL, do show it. I 'm pretty sure 5.17.1 (branched Dec 1) does not. HTH Robert