Ok, when I first saw this thing on high-speed video I was completely stumped! Turns out I was doing a lot of experimenting with this system all the way back in 2018, and since then I hadn't thought much about the how and why of the oddness of this gas piston's motion. But then it came to me yesterday, after I'd already filmed everything for this video! So at that point I was still blissfully ignorant of what was going on. It'll be interesting to see how many people figure it out!