Valid EAN dissapear on the site in a while

[cattty]

Hello,

recently I have noticed that the valid EAN numbers are being constantly erased from the site. We have a database soft (Danea) and a module (PrestaDanea) which connects the soft with the site. In the database soft there is an option to import the EAN numbers which is currently switched off (because a lot of goods have codes different from EAN).

 

At the beggining I thought that the problem was in override between the site and the soft, but then I found that EAN of the product with no changes (quantity, pictures, description) are being cancelled as well.

 

When we edit the product online, we add EAN manually. The system accepts it and it is easily imported to Ebay. Then gradually the EAN start to dissapear. I found entire brands with no EAN numbers even though I was concious to insert and to see them afterwards. I cannot connect any action which might lead to it.

 

Any ideas where to start to resolve the problem?

Prestashop 1.6.0.14