I had a strange situation where data "changed itself"..

The data from tuesday is all correct.

Here is a short sample:

MAINKEY
.......
xxx*dddd
sss*dddd
www*dddd
rrr*oooo
www*wwww

Suddenly on wednesday the data looked like:

MAINKEY
.......
xxx*dddd
sss*dddd
www*dddd
www*dddd
www*dddd

What's happened is a from a certain part in the table down all field values (in one indexed field only!) have been propigated down in the table.

They did have a problem (coincidentally) with an unreleased lock on the record above where the propigation occured (in this case sss*dddd) so they ran a utility that does UNLOCK ALL (but it was on another table...)

We don't have any code that does a replace all or a replace from this record down (i don't even know what the command is!)

Can data in one field change from data corruption or by some error that I don't know about..

thanks..
Looking for an explantion if there is one..