[UPDATE – This is a normal phenomenon, and the phone is functioning as per normal.]

Nothing explained that this is a common occurrence. The Phone(3a) series is well-sealed and complies with the IP64 standard. Therefore, to prevent speaker noise caused by differences in internal and external air pressure, Nothing has incorporated a pressure equalizing hole on the back of the phone. This feature helps maintain pressure balance without compromising the device’s dust and water resistance.

When the phone is pressed firmly, a temporary pressure imbalance may result in speaker noise. However, as the pressure equalizes, the noise disappears. Similarly, once released, the pressure stabilizes, and the sound returns to normal.

Rest assured, this does not affect normal usage, and both the speaker and the phone’s airtightness remain intact.