The start or stop sound is not heard when recording movies.

Confirm that Audio signals is set to On.

When the camera is connected to an HDMI device, no movie recording start/stop sound is produced if HDMI Audio Out. is set to On.
If you set HDMI Audio Out. to Off, you will be able to hear the movie recording start/stop sound, but audio will not be output to the connected HDMI device.

NOTE: Depending on the model, some functions may not be available