A good signal would probably be dithering as you mentioned above - either scrolling back and forth through sections or navigating through different components if you website has a paged layout.
Additionally, as a business, you want to make sure users are following a pretty predictable flow through some limited entry points (like homepage, FAQ, information bulletins) - then either to pricing and then additional information or additional information then pricing (then, ideally, a sale).
If a user is returning to the entry point (i.e. a flow like information bulletins > home page > FAQ > information bulletins) and that happens enough then you can assume that some information users want after the FAQ (maybe, ideally, you think the pricing) isn't being delivered to them and so they're returning to their entry point to see if they browsed the information incorrectly.
If you've got good stats on how far down on a page people are scrolling that could also be something helpful to detect the specific UI issue I mentioned in the post above.
Edit:
I might suggest Don't Make Me Think by Steve Krug[1] as a resource if you'd like to learn a bit more about user flow analysis.
1. https://en.wikipedia.org/wiki/Don%27t_Make_Me_Think