Hello lowfatal,
Thank you for your post.
Could you please send us two screenshots: one from the Video Splitter that has the audio wave and another where there is no audio wave.
Go two Tools -> Show preview filters -> make screenshot of this window or click on the Save all and send created files from two Video Splitters.
Also please record log files from the Video Splitter that has not audio waveform. To get them enable recording of the log files in the Tools -> Looging -> Enable log. Then open your file (the waveform will not be). Then go to Tools -> Looging -> Browse logs -> send us the content of the "Logs" folder.
Thank you in advance.