Amazon's Alexa randomly laughs at users and nobody knows why

Several people who own Amazon's Echo speakers have reported a strange bug: the Alexa voice assistant has been laughing for no reason. Some users on Twitter and Reddit say the outbursts have been entirely spontaneous. Others have said that Alexa has laughed after being asked to turn on the lights -- and may have misheard the command. "Having an office conversation about pretty confidential stuff and Alexa just laughed," Twitter user @DavidSven wrote recently. "Anybody else ever have that?