[noggin]

THIS IS VERY IMPORTANT Otherwise it does not allow the pass-through
This command is a bit misleading, it should be in the audio section, since it affects the pass-through.

The reason it's not in audio settings is that the audio aspect of it - which is clearly explained will disable pass-through - is a side-effect.

The real purpose for that playbacl option is to allow 23.976/24 fps content to be sped up to 25fps for replay on displays that only support 50/59.94/60Hz content and where people don't like 3:2 pull-down (so it simulates PAL speed-up, avoiding 3:2 judder), or to allow displays or playback solutions that don't support 1000/1001 modes to display 1000/1001 content without frame repeats (so it speeds up 23.976fps content to 24fps for playback solutions that can't handle 23.976 natively). It's very much a video-related playback option - as it's there to optimise video quality on playback / display solutions that would otherwise be heavily compromised.  These days it's far less likely to be required - as most displays and playback hardware now support 23.976/24/50/59.94/60Hz replay and refresh (some also support 25 - though with 50 support it's largely irrelevant)

Because of the speed change it can't implement pass-through - as Kodi has to process the audio to change its replay speed to match the video, whilst keeping a standard audio sample rate. The audio issue a side-effect, that's all.

(This setting causes a lot of confusion because people confuse it with 'Adjust Refresh rate' - where the output refresh rate is changed to match the source's refresh rate)