I've noticed this for the past few days, but waited to flag it until I was sure it wasn't forum-specific.
Every thread now has a single "Reply" button at the top under the title, which takes me to the Quick Reply box at the bottom of the page. Replying to specific posts with quotes now requires selecting the "Quote" button on the post followed by "Insert quotes" then finally "Quote these messages".
Google Chrome (49.0.2623.75 m). Issue also verified with Internet Explorer 11 (v11.0.9600.18097)
Every thread now has a single "Reply" button at the top under the title, which takes me to the Quick Reply box at the bottom of the page. Replying to specific posts with quotes now requires selecting the "Quote" button on the post followed by "Insert quotes" then finally "Quote these messages".
Google Chrome (49.0.2623.75 m). Issue also verified with Internet Explorer 11 (v11.0.9600.18097)