Updating specific post parameters with h-update

When sending a Micropub h-update request if the whole post body is modified the changes are applied, but when trying to update an specific post parameter (like syndication) instead of the whole post body the request gets processed without any errors but the changes are not applied.

The results are the same when using a Micropub client like Micropublish or sending a POST request.

Which editor do you use?

Not sure if by "editor" you mean Micropub client, but I tried updating the syndication parameter using Micropublish and sending an HTTP Post like is explained here. When manually updating the parameter in GoBlog's Editor or updating the whole post body with FrontMatter included on Micropublish it works.