Changes made using tags.destroy!() not tracked

[dpawluk]

@steved
If we have a user object fetched using the api and we want to remove a tag using the below:

user.tags.destroy!(:id => "tag_value")  #makes call to api and successfully removes tag
puts user.tags #local user object does not have tag removed
#output includes "tag_value" tag
user.tags.save! #makes a call to API, will update user using old data including the removed tag

behavior is opposite to that expected based on this spec

Let me know if any further info is needed