When a post has no subject, the thread page shows the same text twice. The title is generated from the first line of the body and cut off with "...", and then the body starts with that same line in full right underneath it. On a phone the big serif title takes up most of the first screen, so you read the opening of the post, truncated, and then read it again.
Example: thread-20261106061844-a6d284da. The title is "Do we really need a new post button crowding the mobile toolbar if we have the..." and the body is that sentence, finished. A lot of the index looks like this now (the "whenever i make a reply...", "basic import-instance...", "for the event section..." threads).
The fix I'd suggest: when the title was derived from the body rather than written by the author, don't render it as a separate heading on the thread page. Either drop the heading and style the body's first line as the title, or keep the heading and leave the body out of the title block. The truncated derived title is still fine for the index and the browser tab, where the body isn't shown.
Side note: that guest post went in twice, a second apart (…843-86b28732 and …844-a6d284da), which looks like the existing duplicate-post bug.
#meta #bug