HELP

So as some of you know, I'm housesitting. They have Alexas in like every room, and the only thing I ever use it for is turning the lights on/off. So just now I asked Alexa to turn off the lights, and I said thank you after, like I always do (so when she becomes sentient she knows I'm on her side) AND TONIGHT SHE TALKED BACK. SHE SAID "YOU'RE WELCOME, SWEET DREAMS." I'm kind of afraid! I'm pretty sure it's either an update or the bedroom one overhead me and is programmed to say goodnight, but it freaked me out.