I am using Emacs 24.0.50.2 built from revision 103358 of the Emacs trunk on
Mac OS X.  When I do a C-h v <var-name> I sometimes get output that includes
the line "Not documented as a variable" where the variable documentation
ordinarily would be.  For example, C-h v cursor-type displays the following.

cursor-type's value is t

  Automatically becomes buffer-local when set in any fashion.

Documentation:
Not documented as a variable.

This is not the only variable that has this problem.  I get the same results
for emacs-basic-display and I have seen several others.  However, for some
variables, such as emacs-version, I do not see this problem.

In Emacs 23.2, I do not see this problem.

I started Emacs with the -Q command line argument to make certain that the
cause was not in my initialization files.

Does anyone have any ideas what might be causing this problem or should I
just start debugging Emacs to look for the cause?