Populating a select field from another channel's entries is not working

I created a field group and channel to pre-populate a select field of another field group:

The Source for the Select Channel: Types - Channel (Types)’s Field Group: Type

Field Group Type’s Fields: Item Type (text)

The Select Type: Select Pre-populate From: Types (Type)

But when I make that choice and hit “save” it doesn’t save it. The select shows as empty and when I go back into the field’s settings, it’s no longer set to “Type”.