Two "Approve and schedule" clicks a second apart both went out: the networks answered that an identical post had just been created, and the second answer overwrote the first. Now the server lets exactly one send through per post and tells the second click the post is already on its way; on the Drafts and Review page every button of the card switches off with a spinner while the request runs. The review buttons are labelled for what they are: OK means it passes the content rule, publishing is the buttons on the right.