Amazon responded to requests for comment by saying that the company was aware of the issue and is now "working to fix it".
"I thought a kid was laughing behind me", the person said in the tweet.
As The Sacramento Bee reports, some Alexa users have heard random giggles from the virtual assistant in recent weeks.
The company did not provide any further details, including whether it has any insight into what is causing the Echo devices to laugh spontaneously. "After the third request, Alexa stopped responding and instead did an evil laugh", the user wrote. Freaked @SnootyJuicer and I out.
The unprompted laughter was a trending topic on Twitter for a while.
It's been reported on several occasions that Alexa-enabled devices can be triggered by ambient noises or sounds that go off in the same room, such as commercials.
The latest tech device that's got Twitter talking is Amazon's trusty companion and intelligent personal assistant, Alexa.
Last month, an Echo owner complained that a commercial had a man asking Alexa to order him some cat food. Amazon sold about 11 million Echo devices containing Alexa by the end of 2016.
Streaming Deezer on Alexa will come with a handful of features beyond simply asking Alexa to "play music on Deezer".
Amazon has since acknowledged the issue amid a stream of social media users bringing attention to it.