I have two custom fields in my Invoice module (with labels "BTW"  & "CONTRACT"). Whenever I create a new contact in my Invoice module, I can enter these fields. I have set up synchronization between the modules CRM and Invoice.

However, when I create a new contact in CRM and this new contact is synchronized, the value of the custom fields is synchronized correctly, but somehow the labels of these fields of the new contact are sudenly emptied by the synchronization proces (so the labels don't contain the words "BTW"  & "CONTRACT" anymore).

So the values are synchronized, but the labels are removed. Please advise

Vincent