Recurring mason_data Permissions Issue

I just started getting a really strange error with my RT (3.8.2) installation.

At least once a week the permissions in the mason_data directory get
screwed up, resulting in errors like this when I try to access the web
interface:

Couldn’t create object file
/opt/rt3/var/mason_data/obj/3452752852/standard/index.html.obj:
Permission denied

If I remember correctly one of the directories ends up being set with
root as the user and group. I’m afraid I forgot to check last time it
happened so I can’t be sure.

I see NOTHING in my RT error log. My apache2 error log gives me:

(9)Bad file descriptor: apr_socket_accept: (client socket).

To fix it I just chown/chgrp/chmod and everything works again, but it
happens frequently and the root issue needs to be addressed.

I found this thread:
http://www.gossamer-threads.com/lists/rt/users/43558 but it doesn’t
really contain much useful information.

The issue doesn’t seem to be precipitated by anything, though
sometimes it happens right after one of my users comments on a ticket.

Anyone have any ideas?