Thank you for answering.
These are the OS specs (better more than less

)
Windows 10 Pro edition
Version 21H2
Installation date: 04/11/2020
OS Build 19044.2604
Windows Experience Feature Experience Pack 120.2212.4190.0
Regarding the second question, I don't really know how I can help. I have tried to describe precisely what I do and analytically tell what happens.
Trying, plus I can only say that I work with a "hp elite x2 notebook" and that I tried (not being a computer scientist) to do these things:
1. I put all the default options in the settings;
2. I worked with only one book at a time;
3. I have tried both single-page scrolling and continuous flow;
4. I checked that there was consistency between the scrolling mode used and the option chosen in the pagination preference settings.
I hope we can do something to fix it because I'm in love with caliber but these constant page jumps while reading or underlining make me hysterical.

In the meantime and in any case, thank you so much for your availability.
Giampy