I am running Moodle 1.9.11+ (Build: 20110330) on a CentOS box. The problem we are having appears to be isolated with one user at this time. When this Teacher goes into her course and clicks on "Turn editing on" it logs the teacher out of Moodle, now when myself as an Admin or another Admin logs in to her course and does the same thing it logs us out as well. If we go into a different course and try it, everything seems to be working just fine. This problem is happening with all of her courses.
Testing I have done already. We have two Moodle sites on one server both running the same version. Main Moodle site is /moodle the second Moodle site is /summer_school.
I backup the course delete the course and restore the same course on the Moodle site same problem.
If I backup the course then import it on the /summer_school Moodle site it works fine.
Any help or suggestions would be appreciated.