Clear the cache, or redownload it after clearing the cache and try it again. Facebook literally updates 2 to 3 times a day, one in the morning one in the afternoon and one at night, so you kind of got to be on top of updating it.
Mine was doing the same. The feed would only load one post at a time while scrolling. That seems to be fixed, but now I can't read sub comments unless you select all comments.
