kcm_touchpad apply is always inactive

I just installed a fresh install of OpenSUSE on my laptop, and have run into a problem when I want to configure my touchpad.

No matter what, the apply button in the touchpad settings remains inactive.

It feels a lot like this bug I found bugs.kde.org/show_bug.cgi?id=449843

I have since found this, so it seems a confirmed bug https://bugs.kde.org/show_bug.cgi?id=501315