I noticed just in the past week. When I left for Europe on Oct 1, my flight showed up with an aircraft about 48 hours in advance for both flights. For my return on Oct 11, the aircraft didn't show up until around the time of boarding. Hopefully it's just a temporary glitch and they will start showing up more in advance. It's nice to track your inbound flights to give you an idea if there may be a delay with your flight (I know they can always swap equip so it's not 100%).