DJI Support. Please review and test the following video format settings for a repeatable low sound problem:
4K at 100fps
4K at 120fps
2K at 240fps
If repeated on your DJl Action 2 - please correct this audio bug and include in the next firmware update. Thx

Hello there 10-Bit. Thank you for reaching out and for giving out these information. I will forward these matter and information to the designated DJI Department for attention. Thank you.

DJI Stephen Posted at 8-6 19:20
Hello there 10-Bit. Thank you for reaching out and for giving out these information. I will forward these matter and information to the designated DJI Department for attention. Thank you.

Hi DJI Stephen,
Have used 120p quite a bit now and 2.7K footage has turned out very nice with good stereo sound and normal volume.  It seems when using 4Kp120 - the audio also switches from stereo sound to mono sound on its own accord.  Please forward this additional information to your technical firmware and software departments.  It could be as straightforward as inputting amended code to ensure stereo sound in the affected video resolutions.
Thx

10-Bit Posted at 9-4 16:04
Hi DJI Stephen,
Have used 120p quite a bit now and 2.7K footage has turned out very nice with good stereo sound and normal volume.  It seems when using 4Kp120 - the audio also switches from stereo sound to mono sound on its own accord.  Please forward this additional information to your technical firmware and software departments.  It could be as straightforward as inputting amended code to ensure stereo sound in the affected video resolutions.
Thx

Hi there 10-Bit. Thank you for the reply and for giving out these additional information. If you have any other concerns or any  inquiries with DJI in the future. Please feel free to post it here at DJI Forum. We are all here to help and assist you. Thank you. .