As reported by mina in https://moodle.org/mod/forum/discuss.php?d=253027:

1. I'm beginning with this screenshot, showing a problem with some localisations (here, french) and the CSS rule for the "a" element in the forum discussion view.

CSS rule

#page-mod-forum-discuss .forumpost .row .topic .author a::after

has a "display: block;" property, which make the string beginning with a comma very strange. Suppressing this property solves the problem.

2. Another one. On the forum discussion list, the last column is too tight, which makes the rows too high.

Adding width: 17%; to the following CSS rule makes it a little better.

th.header.lastpost