If you have been working on search engine optimization projects for a while, you will likely have noticed the following situation: On the Google search engine results page (SERP), listings for completed projects either display the intended SEO title plus meta description or the title followed by the initial text string of the page. This can be disappointing when considering the work that goes into setting up these titles and descriptions based on advice that Google has previously given.
As can be expected, SEO professionals wish to showcase certain elements that they make efforts to set up and establish. If a meta description is written and coded for an informative article on a corporate blog, it is for the benefit of describing content to web searchers. As the Google search engine algorithm continues to develop and change, it seems as if it is either ignoring meta descriptions; in some cases, it even chooses to display text on the SERP that is not found on the page.
Whenever you run into a SERP description that is not the page, you can blame Google's semantic machine learning routines, which are coded into the algorithm, for making things up. It seems as if everything Google is doing on the SERP these days is centered on providing information snippets, which are closely related to search queries. Depending on how you look at things, this could be good or bad.
The SEO work you put into your clients' web properties is designed to ensure that the listing will eventually rank on the Google SERP, but there is no guarantee that titles, meta descriptions, and other on-page SEO elements will be displayed. The bottom line of the Google SERP is that is owned and managed by Google; there is no way to opt in or out unless you specify it on the robots.txt file.
In the end, all websites are at the mercy of the Google search engine algorithm, and this now includes the descriptive information that will be displayed on the SERP. With all this said, this does not mean SEO professionals should give up on on-page technical work because it is still highly relevant. For more information click here https://www.reddit.com/r/SEO/comments/hf0cbm/serpshowsdifferentmetadescription_depending/.