Version 61.0.3163.79 running on 64 bit Linux, and I have the problem. Seems to be triggered by the scrolling. After loading the page, I can switch between notebooks and all is fine, but if I scroll any of them a significant amount most/all of the notebook entries disappear from that center column list. if I just scroll a little it's not an issue. E.g., start with "1-10 of xxx" and scroll so it says something like "5-14 of xxx" will trigger the problem. If I just scroll to something like, e.g., 2-12 there is usually no problem.
However, if I click on a tag on the left, the center list shows empty right away, but if I go back to a notebook list, the entries return.
Puzzling!