Problem with Mapping Joomla Fields

Hello,
I have a problem with mapping custom fields to those of Joomla.
I use the Address 1 and Address 2 fields of the Joomla user profile. I have 2 custom fields, one of which is mapped by Adress 1 and the other by Adress 2. When I do the registration, the content of the Joomla Adress 1 field is visible in the 1st custom field and everything works. But if I cancel the registration and I repeat the registration, the custom field is empty and that of the Joomla profile is deleted! It's the same with the 2nd field. It looks like EventBooking when canceling erases the contents of the mapped field in Joomla. It's possible ?

Hi

Cancel a registration should not erase value of a custom field in Joomla core. Maybe when you register for the event for second time, you didn't enter value for that custom field and that's the reason the value of the related field in Joomla core user profile was deleted?

Tuan