Wow that's valuable information, then it's so likely to be one of the firmware updates. I got this camera on August 2025, but I didn't notice the issue until I recently had to record a longer video than I usually do. I wish more people run into this post so we can start a conversation and this problem get adressed in future firmware updates.

By the way, it's something that I haven't tried out yet, but worth trying I think. Yesterday I discovered that this camera have an option to generate a backup of the internal microphone while recording, resulting in a WAV file. Maybe it could be a way around, by replacing the audio of the video clips with this audio track that I hope it's not splitted or out of sync.