What I find weird is that I used a 2017 model for a year and didn't have a single issue issue with the keyboard — and I love the feel of it.

But I bought one of the new 2018 models, and I have recently developed a sporadically repeating key or two, which is driving me up the wall. It's a real shame, because everything else about the machine is amazing. And now I'm soon going to have to take it back and get it fixed – because it doesn't seem reasonable that a £3000 machine should have any issues of this sort.

https://github.com/aahung/Unshaky may help you - as a software debouncer, it's far from perfect but should be a quality of life improvement.