Several people who own Amazon Echo speakers have reported a strange bug: The Alexa voice assistant has been laughing for apparently 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? It didn't chime as if we had accidentally triggered her to wake. She simply just laughed. It was really creepy.”

Said another Twitter user, @taylorkatelynne: “so my mom & I are just sitting in the living room, neither of us said a word & our Alexa lit up and laughed for no reason. she didn’t even say anything, just laughed. we unplugged her.”

Laura Labovich and her children, Emerson, 10, left, and Asher, 13, interact with the family's Amazon Echo in Bethesda, Md. (Bill O'Leary/The Washington Post)

(Amazon chief executive Jeffrey P. Bezos is the owner of The Washington Post.)

Amazon said in a statement that the outbursts are due to its smart speakers hearing accidental orders. “In rare circumstances, Alexa can mistakenly hear the phrase 'Alexa, laugh,' ” Amazon said. To fix the issue, Amazon is disabling that command and changing the trigger phrase to “Alexa, can you laugh?”

Amazon is also changing Alexa's response to that command: Rather than have the assistant laugh right away, the cackling will be preceded by the sentence, “Sure, I can laugh.”

It did not say how many people have been affected. Amazon did not say why the speaker would laugh when no one is talking.

This is not the first problem Alexa has had. Some Echo users reported last week that the voice assistant was down for several hours, drawing comparisons to Amazon's Super Bowl commercial, in which the assistant lost its voice.

This post has been updated with a statement from Amazon.