It’s not an oversite – in principle, plugins don’t know anything about the host and that has been deliberately true for scriptlets (which are plugins) as well. We have been slowing giving scriptlets more “access” to host stuff but it hasn’t been a high priority
So, it seems that the scriptlets in a rackspace are Activated for the first time prior to the execution of the Rackspace Script.
Thus, if the scriptlet, on activation, reports on the value of an environmental variable set via Rackspace Script, it will report the previously open rackspace rather than the current (new) one.