After accepting waiting list, payment form shows field not belonging to category

Hi, I cannot figure out how to setup fields or other options to get this behaviour:

• Registrant receives mail with "there is a place available, please click here to confirm and pay your registration"
• Registrant clicks
• Form shows with pre-filled fields with waiting list information, and payment options

What happens is

• Form shows with pre-filled fields with waiting list information, and (not filled) required fields (Adres) which do not belong to the event.

See attached screen shots.
The event "test" has only category "Bal". While the unwanted fields, f.i. "Adres", have been assigned to other categories. (We need address information when we have to mail something to the home address, so unpublishing is not an option. However for other events we do not need adress information, more strongly, we are not allowed to gather them because of privacy regulations because it is not needed for any purpose.)

If anyone can suggest some solution, would be much appreciated.

Regards Frans