How to get a Lookup Field to Auto-populate when you import into the Related Field

I realized what I did wrong. I have 3 parent-children relationships setup like this in one form so I have all 3 lookups rolling up into one field by using the dynamic form rules. It was a limitation of that rule that was causing the error. I got rid of that and used a formula instead. All of my lookups are pulling properly. I apologize for the confusion!