The link underline on hover appiar upper the link's text when written Wikilinks at the sentence beginning of discussion page. I confirmed with Chrome and Edge, not reproducible with IE and Firefox.
It is probably caused that the HTML tags are arranged in order "<a href=""><span data-mw-comment-start=""></span>Link's text</a>".
It can be seen in several language wikipedia.
Examples:
https://en.wikipedia.org/wiki/Wikipedia:Teahouse#Chopsquad_DJ_Page
https://en.wikipedia.org/wiki/Wikipedia:Teahouse#Draft:Princess_Omowunmi_Agunbiade
https://ja.wikipedia.org/wiki/Wikipedia:バグの報告#表の見出しがおかしい
https://ja.wikipedia.org/wiki/Wikipedia:バグの報告#段落冒頭の内部リンクの下線が上線になっている