Article creation date changes to current time

[adus]

I'm working on a local installation..
I changed in most of my articles the creation date using the editor
Since a  few days the creation date goes to the actual date/time  -and therefor the ordering-
This happens at each refreshing the page (each database request, I think)

Had a look on the database on table elx_content:
Name: created
Typ: DATETIME
Standard: as defined [2006-01-01 00:00:00]
All other fields are empty.
Does anyone have an idea what went wrong?

For your help and suggesstions many thanks in advance

Many greetings from Germny and best wishes for the New Year
adus