Kind of inherent to its nature, pressure sensing device like TrackPoint has too much precision and dynamic range to be hardware zeroed.

Instead the firmware takes average value over time and regard that as the current neutral, and if your finger is on it longer than that integration period, the sum of mechanical imperfection, planetary gravity, heat, whatever noise AND weight of your finger all combined becomes a new zero point.

The solution is to lift your finger off of TrackPoint and letting it wander until pointer stops. There’s nothing mechanically wrong or damaging in and around that, again, just how it is. Same as how digital kitchen scales or body weight scales need to calibrate itself upon powerup, except TrackPoint does it on the fly.