Table Multi-Select not saving?

Using V14
I created a Table Multiselect Field for the Lead Doctype. The Child Table (named Competition Providers) has a Link field which is linked to a DocType called Service Providers.

I can select the field within the UI, but when I click “Save” nothing is saved to the Lead DocType…

What am I doing wrong?

Make sure the link field in the child table doctype has “in list view” checked