The redditor under the nickname helloiamjack learned this, who found a moment from Demon's Souls in his gallery. In the video, he kills the knight of the tower, after which he issues a victory cry.

First time Souls player. I didn’t realise that the PS5 records your microphone’s audio whenever you get a trophy. Whoops. from r/PS5

If you are terrified of eavesdropping, the achievement recording function can be disabled in the settings. Also, the DualSense controller has a mute microphone button.