Fake. Every single 4-sensor scale (one in each corner post) that I've tried does this.

Huh. I have never experienced this and didn't even know this was a thing. My cheapo Chinesium scale that I bought from Amazon years ago occasionally jumps by a pound or so. I measure myself a couple of times to be sure. But it definitely doesn't "freeze" measurements, as I see a different measurements shoes on in back-to-back measurements.