copycopter ignores lambda values for validation after first eval

[kwerle]

class Driver
  validates :age, numericality =>
    {
      :greater_than_or_equal_to => lambda {|o| o.in_europe? ? 21 : 18 }
    }
end

Will get the first age and cache it, ignoring the lambda forever after.
The validation works correctly - just not the message.