WordPress Auto-posts comments when a new post is posted

I recently noticed that WordPress started to post comments whenever I make a new post with an excerpt of my post as the body. This also happens when another website posts my material.

I recently switched to discus, however WordPress is still posting these comments in the default WordPress commenting system.

I’ve looked all over but I can’t seem to find an option to turn it off, even though chances are I turned it on myself unwittingly.

Any help would be appreciated.