I don't know what is going on with the Korg DS1-H batches in 2025. I have now bought three, all of which I've had to return. Half pedalling initially worked perfectly, but after a few weeks it failed. The same thing has happened to another local keyboardist this year with this model. Once they sort out this issue I will happily buy one (yet again!).
A real shame because when it works, the half pedalling on this model works perfectly with my Nord Piano (3), and means I don't have to lug around the heavy Triple Pedal.