I'm creating a Nintex Workflow for Office 365. In one of my earliest steps, I'm setting up variables that are used in a few places throughout the workflow. Two such variables are actually looks up to a Users (aka People Picker) field in a SharePoint list.

For some reason, each time I open the workflow designer, these two variables show as needing to be configured. If I open up the settings for these actions and simply click save, the issue acts as though it's resolved and I can successfully publish the form. After doing so, I can run the workflow and things behave as I would expect them to. However, once I open up the workflow designer again, I have to repeat the process.

As an example, one of these actions is called "Set RegionManager". As the name implies, I have a 'RegionManager' variable. The action looks up to the "Regions" list in my SharePoint site, asks for the "Region Manager" User field where the "Region Name" field equals the value of the "RegionName" workflow variable.

The "RegionName" variable is, itself, set in a "Set Variable" action and looks up to a "Sites" list, asking for the "Region Lookup" (which is a lookup field to the Regions list) field where the "Site Number" field equals the "Site Number" field of the current list item. 

Any ideas as to why this is happening and what I can do to prevent the behavior?