[TYPO3] reaurl reverts to default url format after a while

[Eliott]

Hi everyone!

I've been working with typo3 for 3 years now, but this is the first 
problem that totally puzzles me.

I am running 3.8.1 with realurl version 1.2.1. It is a fairly large 
install with about 20 domains and 600 pages.
For the majority of the domains everything works fine, however for one 
or two tend to 'forget' the configuration that I've set in 
localconf.php. This happens about every two months with all menu links 
reverting to /1234/ url format from the specified. (linking to the 
/1234/ pages gives a 404 error.) If I clean the page cache the menus 
render just fine.

I am sorry but since it comes irregularly and without any intervention I 
can not give any specific details on how to reproduce the problem. I 
hope that someone has already seen this behaviour and can help me fix this.

Regards
Eliott