You cannot source information for a Multiple Select field type.
If your field is a List/Record field, the field selected for the Source From field must be in the record type selected as the List/Record.
Sourcing from body fields to line fields is not supported in SuiteScript
The field selected from the Source Filter by list must be in the record type selected as the List/Record.
A custom field with a sourcing relationship is not available for mass updates or inline editing.
The information is sourced into the custom field only when the record is created or if the specific fields involved are altered when editing the record
To use a Store Value, the custom field must define the Source List and Source From fields on the Sourcing & Filtering subtab.
By storing a sourced field, the sourcing automatically fills the custom field with a value when the primary field, defined in the Source List field, is changed.