Provider configured the regular expression validator for the order attribute in PBA Provider Control Panel at Configuration Director > Sales & Financial Settings > Attributes. For example, the following validator was configured (it allows only 'BC' and 'BF' values):
However, PBA Control Panel allows to enter any value for the configured attribute, so validator does not work correctly.
The problem is caused by the defect PBA-46728 in PBA.
Upgrade to PBA 5.5, the problem with ivnalid values of order attributes entered in PBA Control Panel is corrected in this version.