[BobHelm]

I usually read books on my computer monitor rather than shift it to a device.
I don't maximise the viewer page as the monitor has a 25" screen.

I use the mouse & left click on next page by clicking the arrow in the right hand margin of the page in the reader.
This used to work perfectly for me but now the mouse click responds with a new page where the top x number of lines are old lines from the last page rather than just a clean new page starting where the other one ended.

I am using Linux Mint 20.3 on my computer & Calibre version is 6.3