ratsolve weirdness



I don't know if this is a bug, local quirk, or what, but ratsolve seems
to be giving me a wrong answer here:

Maxima 5.9.1.1cvs http://maxima.sourceforge.net
Using Lisp SBCL 0.8.20
(%i1) ratsolve(d=sqrt(h^2/a^2+k^2/b^2+l^2/c^2)^-1,a);
                                    b c h
(%o1)                      [a = - ---------, a = 0]
                                  b l + c k

This is obviously nonsense because the solution doesn't even contain d.
 Did I flub it up somehow?  Can anyone reproduce this?  Is it expected?

CY

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