I suspect the change we are seeing is that Google is now using a neural network to (re-)interpret the search query.[1] Presumably that neural network also calculates some sort of neural hash for document/paragraph/sentence similarity. The upside is that it can correct more typos, intelligently drop irrelevant terms and understand the meaning of the query to some extent. But the downsite is less precision when you know exactly what you want. It sometimes even seems to ignore the quotes syntax for exact string matching. Very frustrating and very poor quality control.

[1] I bet they train these models based on unsuccessful queries as inputs (in which the user did not click any search result), and then the final search query after which the user left as desired output.