please have a look at the signal path.
source has already 88.2 kHz, interspeaker connection is wireless (though limited to 96 kHz)
why does it show a sample rate conversion from 44.1 kHz (??) to 96 kHz (= correct) ?
i tried that also with other sources > 44.1 kHz, same behaviour.
Not something I’ve come across, and I get exactly what René has.
Either ways, LS50WII doesn’t downsample anything to 44.1kHz. Any downsampling is carried out purely in line with the interspeaker connection type. I’d try rebooting your Core.
If you can recreate, and then immediately send a log in the KEF Connect app, then our app guys can have a look, but as we’ve not changed anything on our end (to my knowledge) in regards to Roon, I think raising with @support would be useful as well.