A major Google update that actually made video results on desktop similar to those on mobile. Instead of a thumbnail for each video, a "carousel" of videos that can be "rotated" to reveal more videos is now displayed.
The number of queries showing a carousel of videos increased by 40% (compared to the number of queries displaying pictures previews before the update). At the same time, the percentage of queries still displaying previews dropped below 1%.
Other than that, the new carousels does not appear to compete with other display types in the organic results, such as the sidebar or local results. In fact, in some cases you can see a carousel with several videos and next to it the old format of videos results.
When did a problem start with the update?
In some cases, pages containing written content (and a short and meaningless videos), started appearing on the carousel. In other cases, pages containing code referring to videos (but no actual video) also appeared on the carousel.
As a result, search engine users started referring to these pages as unimportant, and CTR dropped significantly.
The good news is that on August 13, 2018, Google launched a fix for this issue, and a large portion of the irrelevant pages were removed from the carousel.
What to do if your site has been damaged?
If you think your site has been damaged, John Mueller from Google has some tips that might help you:
1. Block robots from crawling video files and images that look like previews (using the robots.txt)
2. Submit a video sitemap and specify an expiration date for existing videos on the site
Other users have also found it helpful to hide video markup information (Schema Markup)
If nothing works, it is sometimes better to remove the video completely (please see the Medium case).