In order to avoid consumer fears of introducing eavesdropping devices into their homes, most smart speakers are designed to not record any audio unless they hear "wake words".
For Amazon's Echo devices the wake word is Alexa, while Google devices and services require users to say "Okay, Google" or "Hey, Google" to activate the device.
The Google Home Mini also features a button which can be held so users can ask the digital assistants a question.
However, the bug - which was rapidly patched by the company last week - left the devices believing that button was being held down all the time.
The issue was discovered by Artem Russakovskii, who received a review unit of the £49 speaker from Google.
Mr Russakovskii wrote for the Android Police website of his discovery of the issue, and of how Google PR went to his house to retrieve the faulty unit.
In a statement, Google said: "We learned of an issue impacting a small number of Google Home Mini devices that could cause the touch mechanism to behave incorrectly.
"We rolled out an update on October 7 to mitigate the issue, before Google Home Mini is shipped to anyone in the UK."
The number of devices believed to be affected by the bug is quite low - being limited to devices given out at a "Made by Google" event in the US, the company informed Sky News, however it may still cause concern for British consumers.
Mr Russakovskii wrote that the update seemed to work by turning off the touch panel functionality in its entirety.
The company told him that it was "in the process of building a long-term fix, whatever it may be" but Mr Russakovskii said it was "too early to say if they're going to be able to deal with 'phantom' touch events entirely in software or if a recall for affected units will be in order".
Source : http://news.sky.com/story/google-home-mini-was-eavesdropping-on-consumers-11076195