SharePoint Designer Workflow suspended when you have a blank lookup field

I've noticed an issue when you're using a SharePoint Designer workflow, and you use the Current Item:LookupField in a task or an email, and that lookup value is blank, and you're setting it to use Lookup Values, Comma Delimited

You'll get an error of something like: 

System.InvalidOperationException: Values must be bound to a non-null expression before ForEach activity 'ForEach<DynamicValue>' can be used.

If you set it as a string, you'll see the JSON that's coming back, and for empty values it returns the string: 

{"results":null}

Since Designer can't seem to handle that null object, for any lookup values you can do the following:

1)  Save the value as type String
2)  Test for the empty/null case by testing for the {"results":null} string
3)  Then set the value accordingly

So in my case, I've setup my lookup values as such: 

Where in Step 1 I'm using Current Item:Site Access As String, and inside the if statement I'm using the Current Item:Site Access as Lookup Values, Comma Delimited.