The description that appears under your page title in Google search results is called a meta description. You can write one yourself, but Google does not always use it. Google will replace your description with a different section of your page if it decides that section is a better match for what the person searched for. This means Google is trying to show the most relevant information, not necessarily what you want people to see. It is not a penalty or an error. It is just Google making its own judgment about what will help the searcher. Do you think website owners should have full control over how their pages appear in search results, or is it better to let search engines decide?