Microsoft isn't the only one. I review the audio logs from my son's Alexa and it captures all kinds of non-Alexa-related utterances. None of this is shocking, actually, Smart services need a lot of training data to work well. If anything, this just reinforces my discomfort with Internet-connected microphones.
Microsoft contractors were also revealed to be listening to calls made using the Skype telephone service, which is owned by the company.