How to achieve case-insensitive highlighting of search words in the search results of the com_search Joomla component?

Question

Joomla

I use the com_search component to search on the site:

For example, in the search field I type the word "Download" with a capital letter and the searched words are highlighted:

But if I drive in with a small capital "download" only one word is highlighted, and the rest are not:

Maybe someone came across tell me where to dig ? How to solve the problem of case-insensitive highlighting of search words?