So I have noticed that the arrow key scrolling when using the hand tool has somewhat inconsistent increment sizes. If I press the up or down arrow key once the distance scrolled is about half a line. If I hold down an arrow key to begin the fast scrolling, then let go and continue pressing the arrow keys rapidly, the increment is more like a line and a half.
I find this inconsistency extremely annoying, especially since the fast scrolling is redundant because of the page jumping that is achievable with the left and right arrow keys, and that the increment for occasional up and down arrow key presses is so uselessly small. This disrupts the reading experience for me.
I've thought about trying to get around this inconsistency by using other pdf viewers, except that I primarily find myself reading password protected textbooks that are only accessible in Reader. There is Shift-Up/Down arrow key that will jump to the next line not visible, but I find this makes it easy to lose your place in the text. The point is, I want consistent arrow key scrolling incrementation.
If any changes were to be made to this, I would suggest getting rid of the inconsistent scrolling increments and instead making them adjustable in the settings.
Hope you are doing well and sorry for the trouble. As described the Arrow key scrolling speed is inconsistent .
As you have the updated application please try to reboot the computer once and see if that helps. Also open the application and go to View Tab > Page Display > Select 'Enable Scrolling' and see if that works for you.