Its technically not every single election where this is an issue; the 2016 Presidential Election works fine, but this issue exists in some pages, and I know what causes the issue already because I did some debugging myself.
https://uselectionatlas.org/RESULTS/state2.php?year=2018&fips=51&f=1&off=3&elect=0&class=1here is a page with this issue.
The issue is that the files on atlas list the polygon definitions of the Counties that perforate cities inside of themselves for only their outer borders and not their inner borders, and are listed before the cities in the map delineations, which causes them to make the perforated cities unhoverable due to the way in which html works.
The reason the 2016 Presidential Election works fine is that rather than listing everything in the polygon definition section in standard FIPS order (which puts all the Counties 1st and all the Cities 2nd); it goes in complete reverse FIPS order, thereby placing all the Cities 1st, and all the Counties 2nd.