Drop fields not working in filebeat

I'm trying to remove fields by using the drop fields, the syntax is as follows :

but it doesn't seem to work, any idea why?

Hi!

According to the docs the configuration looks ok.
Can you share the complete filebeat's configuration?

I think it has something to do with the fields I'm trying to delete, so are there any fields that cannot be deleted?

Can you show indexed document as JSON ?

And please share the full filebeat config if possible.