![](https://lemmygrad.ml/pictrs/image/SCO6kIkrt3.png)
A similar thing has happened with me. It's usually when there's a picture. When I scroll down the picture shrinks, takes up less space and the page slides upwards to fill in the space.
Does it happen more with threads where you've opened some screenshots, etc?
'Never interrupt your enemy when they make a mistake' includes when they bathe in pig shit expecting any other outcome than smelling of pig shit and the consequences therefrom.