We have a macbook pro running an up-to-date installation of Mavericks. We do not want to upgrade to Yosemite yet due to our management software still ironing out the differences. Its possibly a bug introduced in a recent update but for some reason over the passed 3-4 weeks we have a macbook which is logging out after 1800s of inactivity.
We do not set this centrally and after some digging we found its set in the global plist. We change it and it changes itself back. we have extended the time and this goes back to 1800s and we have disabled this setting. We have even deleted the global plist and re-booted and its back with the 1800s setting.
I wondered if anyone else had encounter this and possibly ironed it out. Its a strange one.