Orchestration Parameters Changing Mid Run

I have noticed in a couple of Orchestrations recently that the value of an Orchestration parameter is changing mid-way through the Orchestration run. It looks like this is due to having the same parameter name in subsequent steps, for example I have an Orchestration that is reading through a table containing email addresses then calling a child Orchestration passing in the email address as parameter "Email Address". The child Orchestration then uses the email to retrieve the Active Directory email address, ID and name associated with the email address and updates the database table with the missing data