Of the serious, perhaps, only the volume control:
1. There is a real lack of a digital indicator of the current volume level before the signal is applied to the input. The only place where you can see the volume level is the application on the phone. Opening it before turning on the TV is, to put it mildly, stupid. But otherwise, you can be notably scared of the volume.
2. Sound control from the native remote control is terribly slow. From zero to maximum, as well as in the opposite direction, go offhand for half a minute.
3. On the 2022 LG TV, I set up the speakers as a soundbar connected via optics, to be controlled via a universal remote control. Speaker on/off works fine. The volume control works, but, like from the native remote control, it is terribly slow and plus you can’t see the volume level on the TV, they just blink + and -. LG has LG Sound Sync technology to sync TV volume levels via Toslink, but this is unfortunately not supported by KEF. Alternatively, you can connect your TV via Bluetooth, but I'll still experiment.
When streaming via AirPlay, Flac or Bluetooth, the volume can be controlled from the phone (natively or from the application), so this unpleasant feature is only applicable when working with a TV, which is obviously not the main mode of operation for this kit.
The need to have two applications on the phone (one for control, the second for streaming control) is not a drawback of course, but very strange.