Google is permanently disabling a feature on the forthcoming Google Home Mini smart speaker after a reviewer discovered that it was surreptitiously recording his conversations without his knowledge or consent.

The issue, Google says, was that the button on top of the device was faulty and would sometimes activate on its own. In response, Google acknowledged the bug and issued a software update that would disable that button for all users while it explored a long-term fix.

Now that change will be permanent.

This episode is embarrassing for Google as it grapples with Apple and Amazon to conquer the small, but growing, market for voice assistants powered by artificial intelligence.

Here's Google's statement:

"We take user privacy and product quality concerns very seriously. Although we only received a few reports of this issue, we want people to have complete peace of mind while using Google Home Mini.

"We have made the decision to permanently remove all top touch functionality on the Google Home Mini. As before, the best way to control and activate Google Home Mini is through voice, by saying 'Ok Google' or 'Hey Google,' which is already how most people engage with our Google Home products. You can still adjust the volume by using the touch control on the side of the device."

What happened

Google unveiled the $50 Mini, which goes on sale next Thursday, at its event last Wednesday. Soon after, Artem Russakovskii, a reporter with Android Police who received a test unit, discovered that his device was turning on by itself, recording his conversations, and uploading them to Google.

Normally there are two ways to interact with Google's smart speakers, including the Mini. You can say the words "OK Google" followed by a command such as "play 'Bohemian Rhapsody.'" Alternatively, you can press the button on the top of the devices before saying a command.

But Russakovskii discovered that his Mini was listening in on him even when he hadn't pressed the device's button or said "OK Google." When he checked his personal activity page on Google, the site that shows users' interactions with the search giant's services and the data it collects on users, he found sound files that had been uploaded to Google's servers from the Mini without his consent.

Google Home Mini. Matt Weinberger/Business Insider

Google blamed the glitch on a faulty button in some of the units. The buttons on those Minis were detecting touches even when there was no touch to detect. Russakovskii apparently got one of the defective devices.

On Saturday, three days after it handed out the Mini review units, Google rolled out a software update that disabled the button. The change affected all Minis, even those that weren't malfunctioning. The company also says it has deleted all the data purportedly recorded from button pushes on the Mini review units — whether they were actual button pushes or not — from the time it handed out the devices to reviewers until it issued the update.

Ultimately, the problem appears to be a simple error, not a malicious act of spying. And yet, the glitch could both hamper sales of the device as well as undermine trust in Google — trust that's at a premium, as both Google and Amazon work to persuade consumers to let them place microphones in their home.