[TYPO3-dev] sorting field values changing on their own?

[Jan Slusarczyk]

I have a trouble with a large (2200 pages) website. I have a couple of 
places where sorting of articles is especially important. And I have 
noticed that they become out of order every couple of days. I've tried 
sorting them in typo3, then ordered them by hand with mysql. But the 
values of "sorting" field keeps changing "on their own". There is one 
editor in BE and I know for sure that nobody even touches these pages 
and their immediate "parents". No edits are committed to these branches 
at all.

Last time in 7 out of 40 pages the values were changed from 1850xxxx to 
0, a couple seeming random 4 digit values and 10000.

Every day I have a database backup script running (based on mysqldump). 
Typo3 4.2.1, php 5.2.3 with recent APC, Apache2, MySql 5.0.51

Any idea what might be a reason for these changes?

Regards
Jan