That curve goes so close to zero, that you'd think that if there was even a speck of dust inside, the slider would simply stop part-way through the return stroke.
I do have some switches that fail to return; one is CL-1145, which I did include. (I realise now that I also forgot vintage APC green, which is not a model that Tai-Hao still remember.)
I wonder if CL-1145 also comes so close to 0 gf that this is why it's able to get stuck the way it does. Those are used switches, while LARB01 is all new/NOS.