There may have been another unconfirmed Google search ranking update that occurred between October 15th and October 18th. The bulk of the volatility seemed to be around Thursday, the 16th.
Here is a recap of what happened in the search forums today...
Five weeks ago, Google announced a new feature named "Text guidelines" at the Think Retail event. Google said these would roll out "over time this Fall." Well, some are now seeing the new feature.
Google is testing the ability to highlight portions of the response, to do a follow-up question on what you highlighted. It is similar to past tests on the AI Overview, but this is within AI Mode.
Google is testing the paperclip style icon in the search results, by the search result snippets and description. Clicking anywhere on the paperclip or the snippet will take you to the webpage.
Google has added price tracking data charts for each retailer within Google Search. On the right side, after you click on a product, Google may show a price chart with pricing over time. Google may also let you click on the available merchants and retailers to see how the price has changed for that specific merchant over time.