Gary Illyes from Google explained how Google Search may or may not handle special characters within Google Search. He explained this in the latest Google SEO office hours at the 16:10 mark.
Gary was asked, “How does Google handle special characters like the superscript e in search results.”
For example, a Latin letter E with acute like this:
Gary said “if those characters are not displayed correctly in search results that is most likely caused by a mismatch of what Google’s algorithms detected as character encoding for your page versus what you meant to use.”
So in that case, Gary said “you should specify the encoding in your HTML using meta element and its charset attribute.” This is “Especially” important “if you are using funky characters in your HTML,” he added.
“If the character encoding is not specified Google will try to detect it but getting it right is actually a huge undertaking and it’s very very difficult in most of the cases anyway,” he explained.
So if Google is getting it wrong, try to explicitly specify the character encoding in your HTML.
Here is the video embed where he said this:
Forum discussion at X.