The XM3’s are amazing. I live in a state where It can get brutally cold, and I’ve never use them outside in those temperatures, just mainly indoor temperatures. But I can see why the touch sensor would get all wonky, similar to like your finger won’t respond very well to touch ID with cold fingers.
The issue is not about the touch sensor not working. The issue is how it's having its mind of its own. It will keep upping/lowering the volume at will, pausing/starting playback at will, activating transparency mode at will etc.
I ended up with the Bose NC 700 instead and they also have touch sensors but they don't start going crazy when it's cold outside.
I find it strange for Sony, a Japanese based company not testing this. Japan gets cold for several months per year and I'd bet lots of Japanese people use their headphones outside during Winter. I'd bet this is one of those things you don't really think about until you have problems. I haven't tested the new WH1000XM4 but I'd bet they don't have these issues.