This has been mentioned several times and not dealt with by Etsy, so I'm bringing it to the foreground again.
Two things:
First: New messages are not being marked as answered within 24 hrs, even when I answer them immediately. The banner saying to 'respond within 24 hours for speedy service or blah blah blah' doesn't go away after multiple messages to buyer.
Second: The mobile app hasn't been notifying me of new messages for months. I checked all the notification settings, I make sure the app is updated, I uninstalled and reinstalled the app, etc. Still not getting messages from customers unless I open Etsy and look for them. I lost my star seller badge this month because of this. I'm often not near a computer because I'm an artist and I don't sit at a desk all day. An app glitch like this makes it nearly impossible for a seller to stay on top of messages.
To whomever it concerns, fix the dang messaging system!! And don't penalize sellers for missed messages when the system is glitching and not working properly, that's just not cool.