setting "last name" to local is illogical, but the user bapis will set it to the same value as xubname it it is initial.
it is a mandatory field so setting it to local is strange.
you should have set the 2nd names to local or the first name if you wanted to use alternate names for the same identity in the logical systems.
you definately have blocked the cua here, but that it does not use the same logic as the bapis is suspect.
which release are you on?
Julius