Built-in pdf viewer navigate with wrong page number and scroll position
I compared Chrome and Opera even though they use the same Chrome PDF pluggin, only Opera has this problem. On any pdf documents, Opera showed more pages on the screen while Chrome showed less. This indicates Opera got the page dimension rendered wrong. Thus, page number were shown incorrectly as I scroll the scroll bar. Apparently this problem was due to my 4k screen resolution on my laptop (windows 10).