This is apparently a known bug in Tcsh in the particular version of Tcsh and RedHat that I am using. Apparently there is a patched version of tcsh available for this issue, as described in this errata, for RedHat 5.4:
Expansion of multiple filename globs failed if any glob in a command line expression failed. The correct behavior outlines that a glob command should only fail if all components of the command fail. This behavior is restored with this updated package. (BZ#529703)
I checked, and I do indeed have the buggy version of tcsh installed as noted in the bug report above:
$ rpm -qa tcsh tcsh-6.14-14.el5_4.2
Evidently the IT department for my company has not installed this tcsh patch yet (though I recently learned we'll soon be finally upgrading to RedHat EL 6.x).