Workbench access does not reflect vocabulary/term changes

Assign a vocabulary to a workbench in "Editorial vocabulary".
Now change the name ov the taxonomy vocabulary, e.g. from "Simple tags" to "New tags"
The settings page immediately reflects the change, but on the roles and editors tabs the old vocabulary somehof is cached and not updated.

When you change something then (role based acess) then you get a weird PHP error if there were terms e.g. inserted or reordered with hierarchy.
when you cancel and reactivate the automatic section assignment it works again.