My comment widget uses the same fonts in all but the recent comments tab. All of them are like my attached screen2.jpg, except "recent comments" that shows as attached screen1.jpg with a font that is too large.
It's a CSS conflict with your theme or other plugins. To solve it, please navigate to Dashboard > Comments > Settings > Addons > Widgets sub tab, put the following CSS code in "Widget custom CSS" textarea, save it delete all caches, do CTRL+F5 on frontend.
I see another conflict. The code for solving it also provided below.
#widget-comments-container.widget-comments-container .popular-comment-author-body{ font-size: 12px !important; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; width: 61%; } /*To solve the problem with the display of the icon*/ .fa-reply:before { content: "\f3e5" !important; }