Also, why does that button have ellipsis? All human interface guidelines documents that I've read (Windows, Apple and Android) state that ellipsis should only be used on controls that have a follow-up action.
For example, clicking "Browse..." in a file upload control opens a picker, "Print..." opens the print settings dialog (before sending the document to a printer) while "Close" does not have ellipsis appended to it because it's an immediate action.
The button on the previous screenshot immediately loads the post (although it does a roundtrip to the server) and there is no second action which has to be taken. However, the new way of dismissing unread posts and topics should have ellipsis, but doesn't.