In v19.08.2, I seem to have a problem with audio added to the timeline. If I play the audio in the Project Bin, it plays as normal. However, when I place the audio in the timeline without changing anything, the left audio track's volume is reduced. I can't seem to find a way to fix this, I'd appreciate any suggestions.

Please delete the cache. See here: https://community.kde.org/Kdenlive/Configuration or you go to Project menu → Project Setting → Cache Data tab → there you can delete cached data.

I've tried clearing the cache, didn't see, to do anything. Any other things I should try?

i can't see the issue, tried with some clips recorded from different devices, but the audio levels seems ok. (19.11.80 Windows)

I am a new user as of a few weeks with the exact same problem. When I add a MP4 clip, the audio from both stereo tracks plays fine from the clip. When I add the clip to the timeline I only get the right channel playing. If I change timeline settings to SEPARATE AUDIO I can see the waveform for both channels but still only hear the right channel. My version is 19.11.80 It has been this way since my initial install 1 month ago.

Just tried some MP4.. i added a more stereo MP3... made a rendering... and after that reimporting the final render again in Kdenlive .. and audio track are correct.

are you experiencing this using headphones? (is just a small difference?) it's possible to have an original MP4 clip to make some tests?