Steps to replicate the issue (include links if applicable):

• Open https://en.wikipedia.org/w/index.php?title=Operation_Barbarossa&oldid=1109507930#Axis_invasion_plans
• Hover over the linked text "preparing to attack the Germans" to get a preview of the article "Soviet offensive plans controversy".

What happens?:

The preview includes the text <em>Icebreaker:</em> <em>Who started the Second World War?</em> with raw <em> tags.

What should have happened instead?:

The text surrounded by raw <em> tags should be italicized instead. There are two aspects to this problem:

• The preview shouldn't contain raw tags.
• Double apostrophes shouldn't be replaced by <em> tags.

The source ([[Icebreaker (Suvorov)|''Icebreaker:'' ''Who started the Second World War?'']]) uses double apostrophes, which represent italics, not emphasis. According to the Wikipedia Manual of Style,

Other, non-emphasis, uses of italics on Wikipedia should use ''...'' markup, not <em> or {{em}} markup. In particular, words as words, including introduced terms of art, and foreign words and phrases, use normal typographic italics (''...'' or <i>...</i> markup, when necessary). Do not use emphasis markup as an "escape" for italic markup.

Other information (browser name/version, screenshots, etc.):

Firefox 104.0.2 under macOS 12.4

Screenshot: https://imgur.com/a/jIkouYx