with_indifferent_access question Rails 2.2

We had something very odd happen today after installing the twitter
gem. We had a ton of our tests fail. When we removed the gem they
would pass.

What it ended up being was during the building of attributes using
nested attributes setters we were accessing the hash that was passed
in like this:

def shade_preference_attributes=(shade_preference_attributes)
    shade_preference_attributes.each_pair do |key, value|
      value.each do |shade|
        self.shade_preferences.build(:shade_id => shade
[:shade_id], :preference => shade[:preference])

Before installing and configuring the twitter gem in our rails
application this worked fine. After doing it, it started failing.
The failure was because shade (a hash) did not have :shade_id
or :preference in it anymore. It actually always had the keys
"shade_id" and "preference" that never changed, but now the access of
them by symbol started failing.

When I removed removed the config.gem line for the the twitter gem
everything worked fine.

I'm assuming this has something to do with indifferent access. In
both cases the shade is a normal Hash. But, in one case it appears to
be using indifferent access and in another case not. Or could it be
the hash was built using indifferent acces or not? I'm not exactly
sure how that works.

The twitter gem installs a bunch of gems. Has anyone seen anything
like this before.

It's not the twitter gem, it's the mash gem. The twitter gem requires
the mash gem.

These lines at the bottom of the mash gem are causing the issue:
  # Converts all of the keys to strings
  def stringify_keys!
      v = delete(k)
      self[k.to_s] = v
      v.stringify_keys! if v.is_a?(Hash)
      v.each{|p| p.stringify_keys! if p.is_a?(Hash)} if v.is_a?(Array)

This is defined inside class Hash...end inside of the mash