Mobile dev here: the problem seems to be low and inconsistent framerate, i.e. "jank", which messes up the scroll timings and results in weird scroll speed and momentum.
To my eye it looks like the app is doing too much work while generating each element in the list - posts, comments, etc. This is common during early development phases when you're trying to get thing in first, and then address the performance bottlenecks.
It looks like 90's clipart. Oh wait, it kind of is.