I get the same display and return value when I specify the following SQL query in Popup LOV :
select distinct location_name as d, location_id as r from json_table(:P145_RESPONSE_JSON, '$.items[*]'
columns(location_name path '$.participants[*]?(@.actor.kind == "location").actor.name',location_id path '$.participants[*]?(@.actor.kind == "location").actor.id'))
Not quite sure why ?
If I swap location_id as display and location_name as return, it gives me the appropriate values although that's not what I want.
Any ideas to fix this.