I've been experiencing similar issues with many echo devices (pair is 3rd Gen and a 4th, and 2 shows both 3rd gen) I can say this, the utterance is irrelevant because I have been using routines that end in playing music. I know I said the right thing because the routine are working up to the last line.  Example: I say "Alexa, Sleepy Time" and my bedroom lights change from daylight to soft white and slowly fade out over 15 minutes. As soon as the lights change Alexa gives me one of the random "good night" responses like "I hope you count fewer than 10 sheep before falling asleep tonight", then she says "I can't find the station Yoshida Brothers Radio on Franklin's Pandora". I changed the station name to Super Yoshida Brothers in my Pandora app, and in my routine and it's working again. ... View more