Automatically changing Field Name

Automatically changing Field Name

When I'm on the layout page of the module Accounts. 
There is a field 'Bedrijf Nummer' (I've translated the CRM to Dutch). 
When I actually go to the page where I can add a new Account, the fieldname is changed to 'Bedrijf Aantal'. 
This is very (very!) confusing. 

Why is this?