Google isn't just bolding the search query now, but also the answers to your search queries.
Google is now bolding answers in the search results, not just the query or the synonym of your query in the search results.
For example, if you search for [what color is the sky] or [the average age of a college student] or other queries that would return answers at the top of the page or in the search results, you would see Google bolding the answer.
In the first example, Google is bolding blue and red colors in the answer in the knowledge graph box, but also you’d find these words bolded in the actual search results below:
Here is the second example:
Here is a screen shot showing a standard search result with the number 25 bolded in the snippet:
