Bug, Admin menu icon too large

After the most recent update the admin menu icon ends up being too large.
Clearing the cache did not work in Chrome, although it works fine in Firefox.

Comparing a working version, it’s missing the following css
.menu-icon-mec-books .wp-menu-image img, .toplevel_page_mec-intro .wp-menu-image img {
width: 18px!important;
padding-top: 7px!important;
}
from the backend.min.css?ver=5.2.3 file (the working copy does have this and it is on
WP 5.2.3).

This might be the issue because this site is not on WP 5.2.3 yet.