Additional Audio Recording Not Perfectly Synced

[SaxaphoneWalrus]

When recording videos with all three audio tracks in use, the Primary and Secondary are the exact same length and seemingly perfectly in sync however the "additional audio recording" is usually slightly longer, sometimes starts slightly later and ends up getting slightly out of sync if the video is not at a perfect constant frame-rate.

Is there any way to fix this or is it a limitation of recording it to a separate file?

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Capture Mode: Game
Format: MP4
Hardware acceleration: NVIDIA NVENC
Size: Original (1080p)
Framerate: 60fps

[Piotr]

Audio recording to separate audio file may not start in exact same moment as video recording. That is why it may end up being little shorter or longer than video. Usually little shift of audio in video editor is all you need to match both files.