Wordpress install sets wrong group ownership on NFS home

We have 3 cPanel servers and this is only happening on the one with the home directories on an NFS share. When a user installs WordPress through the site software page, it says the software installed without error but visiting the new WordPress gives a 500 error. The logs show a phpSuExec error about the gid not matching. If we go into the user's public_html directory, the wordpress directory shows as having the group 'nobody'. If we do a 'chgrp -R username wordpress', the wordpress site works fine. I also tested by moving the account to a local disk and then the WordPress install set the correct group ownership on the directory.

Has anyone else run into this problem and if so, how did you fix/work around it?