modify specified fields

hello to all.

i have installed vibe 3.4 and try to customize my own entry form.
some elements on that form are checked with "field Level modification".

i have a workflow state "in Bearbeitung" with a Access control element.
that Access control element contains the right "modify specified fields" to the user "admin".

nevertheless all users who can modify the entries are allowed to modify the elements checked with "field level modification".

whats wrong?