preview pdf scrolling (also page up/down) Has anyone else encountered this (below) odd scrolling behaviour in Preview or found a better fix or workaround?

I am using preview (version 9.0 909, 2016) from Sierra (mac OS 10.12) to view pdfs produced by pdflatex.  For preview to stay on current page when the file is rewritten, I have kept my previous settings:

Preview→preferences→PDF→ [✓] Start on the last viewed page
Preview→preferences→PDF→ Opening for the first time: Show as Single page


With the current version the scrolling behaviour has changed.  My document will not scroll in any of the standard ways.  None of these work:


Pageup/pagedown on keyboard
two-finger scroll on trackpad while pointer is over document
one-finger scroll on magic mouse while pointer is over document
Preview→Go→Up


However the following do work:


two-finger scroll on trackpad while pointer is over menu bar or tool bar
one-finger scroll on magic mouse while pointer is over menu bar or tool bar
any of the above if document magnification is decreased or increased slightly (it opens in "⌘9 Zoom to fit" mode)
switching to continuous scroll mode


Speculation: Preview is stuck halfway in its "scrolling within page" mode, as a vertical scrollbar appears, and either scrolls a small amount without the view changing, or doesn't move.  However, it can't scroll to the bottom and then progress to the next page like it normally would.

Preview's continuous scroll mode is my current workaround.  This is tolerable, but I have Stockholm syndrome from previous versions of Preview, where a file change would reopen the document at page 1 in this mode, so Single page mode was my workaround for that.
What seems to be happening is that when we used to set Preview in "single page" as the default, a newly-opened document window was exactly the right size, and you could easily up/down arrow through the pages.   

However, now it instead opens the document with the page ever-so-slightly too large for the window from side to side, so Preview switches into "Oh, you've zoomed in and you'd like to scroll around this ONE page", and so the arrow keys become the scrolling around that ONE page keys.  

Except that since it's vertically the right size, up/down doesn't scroll.  Left/right arrows will, though.

If you slightly enlarge your window (or shrink the page) to include some space all around, you'll see the up and down keys work without the option/alt key.

And this behavior is still screwed up as of 2017-05-29 (OS 10.12.5).