before_type_case broken?

Hey,

I've noticed that I seem unable to get a _before_type_cast value for
dates in 2.1. Specifically, if I assign a date string to a date
attribute, and then call attribute_before_type_cast I get a TimeWithZone
instead of a String:

model.start_date = "2001/01/02"
model.start_date.class = ActiveSupport::TimeWithZone
model.start_date_before_type_cast.class = ActiveSupport::TimeWithZone

Examining the @attributes in AR/lib/attribute_method.rb shows that the
entries are already TimeWithZones, whereas in 2.0 they are Strings.

Has anyone else come across this?

tahnks,
d