Can I search for special characters highlight in Elastic?

I am using ElasticSearch RestHighLevelCilent api in java.

Among them, use QueryStringQueryBuilder to input the string I want to search.

Then, the matched string is wrapped around the tag with HighlightBuilder.

Everything works as expected, except for searches involving special characters.

If I search for an encrypted string (eg apple==), the only thing the tag wraps is apple, except for ==.

How can I get the highlights to include special characters? ("apple==")