I'm a long time Firefox user. Often and certainly in this forum, I increase text size with a corresponding reduction in the amount of information visible at a time. I do this by using Ctrl++. ( A litttle confusing there. That's the Ctrl key and a plus key simultaneously).
I've gotten used to reading the forum this way and am generally satisfied with the way scrolling through a topic works.
Recently, I've started experimenting with Chrome (because I'm not sure what's about to happen to Firefox in version 57).
Scrolling works OK with default text size, but if I increase the size as described above, scrolling becomes very problematic. Most pushes of Page Down result in some amount of text that was just below the prior view being now just above the new view. It could be said that this amount of text is skipped.
If anybody knows how to improve this situation, I'd be happy to see any relevant information, but this is mostly FYI. I don't necessarily expect a solution here.
In response to the obvious question, I don't know if this behavior happens anywhere else. It doesn't seem to happen everywhere.