$old->usergroup; # make sure this is cached for exports
- my $error = $new->process_m2m(
+ my $error = $new->check # make sure fixed fields are set before process_m2m
+ || $new->process_m2m(
'link_table' => 'radius_usergroup',
'target_table' => 'radius_group',
'params' => $new->usergroup,