Bug in lock timeout

We are using Jahia 4.1.0_02 and it happened to our customer that all the 
pages got locked. We told him that the lock will go away after a timeout, 
but the locks were still there on the next morning. On the next morning we 
logged in again and had to stay logged on and wait for the time specified 
in the session timeout. So it looks like you have to stay logged on in 
order that the lock is being deleted after a timeout. If you log off and 
log on the next day the lock is still there. Is there already a quick fix 
for that?

Greetings,
Benjamin