Library and peripheral window behavior

[asw22]

I am presently expurging my Kobo SD from books present in the database, but not physically.
My Library and peripheral databases are quite large (ca 30,000 books). I need to check line after line books considered not present in the library against the library itself to be sure sometimes a book announced at not present is there on the SD...
The goal is to have a peripheral book list reflecting the peripheral written books.
My idea of fun, dont ask

My problem is when alternating between peripheral and library view, the view is not "stable": for instance, on the peripheral view, the list goes back after a while (ca 20 s) to zero. When you are at 15000, it's unpleasant.
On the library view, each time I open it the list has gone back by 500 books or so...
What happens, and what can be done?

It is as much fun as opening a book and systematically begins at first page, whatever the place where you closed your book last time...

Thanks!