SSA field not working???

I am working on an install that has two custom entities that are a child of the Company entity. These additional entities were created to accommodate the way they want to enter oppos and quotes. The additional entities are called Location and Job Sites.

The locations and job sites are both owned by the Company. When a location is entered, it needs to be assigned a Job Site.

Therefore, on the Location table, there is a SSA field to select the Job Site. However, the field does not appear to be working correctly.

When on the Locations entry screen, you can select the magnifying glass for the Job Site and see all the Job Sites for that company. However, when you select the Job Site, it does not populate in the field. I cannot figure out why this is happening.

I tested the same layout in my sandbox environment and it works fine. I don't think that I am trying to accomplish anything out of the ordinary..it just seems to not work on this install and I cannot figure out why.

Has anybody else experienced this and how was it resolved? I have tried to delete the SSA field and recreate it. But still does not work.

Any assistance would be greatly appreciated. Below is how the SSA field is setup on the Location entity.