problems with /tmp under 4.0.3

[Ned Danieley]

We've just upgraded to 4.0.3, and we've been having a problem with /tmp
changing mode from 777 to 775. this happens on multiple machines (3s and
4s), and at seemingly random times, not necessarily just after a reboot.
it does seem to only happen to machines that mount their root from a local
disk. Has anyone seem this behaviour?  the hotline doesn't seem to know
about it.