After some significant checking, it does not appear there is a reliable way, to have an Email step, display the machine a package was deployed to, IF it occurred in a child step.
Parent steps work fine: I just use an Output variable in each package step with the Octopus.Machine.Name , and loop through the steps I want in the email step.
Child steps though, appear to not play nice with Output variables.
Is there any way I can reliably do this? (have access to a Step or Action-level variable containing the machine the package in the step was deployed to - in a Child variable)