Groups with one member

Apologies if this has been answered before, but I didn’t see it on the
Wiki or via a google search

Using RT 3.4.2 on Perl 5.8.6, Apache 1.3x and MySQL 4.0.33, Mod-Perl
1.29 on Solaris 9 SPARC.

One of our admins in Singapore has created a new group with a single
member and using the RTx Rights Matrix I can see that the group member
has owner, take etc rights for tickets in the target queue. However,
when the queue admin uses jumbo and tries to assign it to the member of
that group, her name does not appear in the dropdown for Owner.

As soon as I added a second member (my own login) to the group, both
names appeared in the dropdown.

Is this a feature? bug in our install?

Thanks

Richard