Opus audio - no sound playback 3.0.21 (Linux)

I've encoded a video with audio using Aviator to create an AV1 video with Opus audio. VLC shows the video but doesn't play the audio.

The audio plays fine on Totem and in Firefox.

Here's a sample of the audio (no video) - it doesn't play in 3.0.21 on Linux (Pop OS using the Flatpak version):

blank

I've tried wrapping in both WebM and MKV - both have the same problem.

ffmpeg shows the WebM's codec as:

Input #0, matroska,webm, from 'blank.webm':
  Metadata:
    COMMENT         : "Encoded with Aviator"
    MAJOR_BRAND     : isom
    MINOR_VERSION   : 512
    COMPATIBLE_BRANDS: isomiso2avc1mp41
    ENCODER         : Lavf61.7.100
  Duration: 00:02:32.02, start: -0.007000, bitrate: 82 kb/s
  Stream #0:0: Video: av1 (Main), yuv420p10le(tv, progressive), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      HANDLER_NAME    : VideoHandler
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc61.19.100 libsvtav1
      DURATION        : 00:02:32.000000000
  Stream #0:1: Audio: opus, 48000 Hz, stereo, fltp (default)
    Metadata:
      HANDLER_NAME    : SoundHandler
      VENDOR_ID       : [0][0][0][0]
      ENCODER         : Lavc61.19.100 libopus
      DURATION        : 00:02:32.021000000

If I extract the audio using ffmpeg -i input.webm -acodec copy testing.opus it still doesn't play in VLC.

opusinfo describes the file as:

Processing file "testing.opus"...

New logical stream (#1, serial: b5cda61d): type opus
Encoded with Lavf58.76.100
User comments section follows...
	HANDLER_NAME=SoundHandler
	VENDOR_ID=[0][0][0][0]
	ENCODER=Lavc61.19.100 libopus
	DURATION=00:02:32.021000000
	DESCRIPTION="Encoded with Aviator"
	MAJOR_BRAND=isom
	MINOR_VERSION=512
	COMPATIBLE_BRANDS=isomiso2avc1mp41
Opus stream 1:
	Pre-skip: 312
	Playback gain: 0 dB
	Channels: 2
	Original sample rate: 48000Hz
	Channel Mapping family: 1 Map: [0, 1]
	Packet duration:   20.0ms (max),   20.0ms (avg),   20.0ms (min)
	Page duration:   1000.0ms (max),  993.6ms (avg),   20.0ms (min)
	Total data length: 1393928 bytes (overhead: 0.887%)
	Playback length: 2m:32.013s
	Average bitrate: 73.36 kb/s, w/o overhead: 72.71 kb/s
Logical stream 1 ended

VLC's codec information shows:

And, while playing, appears to decode even though there's no audio output.

For copyright reasons, the above music by Rockot from Pixabay