The TV responds to sound from the surroundings (only TVs with a built-in MIC).

The TV's built-in MIC may pick up sound from the surroundings and respond unintentionally.
Change the sensitivity of the TV's built-in MIC to [Medium] or [Low].

Press the (Quick Settings) button on the remote control, and select the following in order.
[Settings] — [System] — [Built-in MIC sensitivity]