Are double quotes working on Google again?

Not sure what you mean by "works". It still auto-corrects and includes additional results. You have to use verbatim mode (tbs=li:1) to only get exact matches.

I think, they changed the logic some years ago. Before it was meant like "exact that term". Now, it's used as "that term must be in results returned"

You can check that doing Google's advanced search. There is a field, when you type in your search term, it will be put within double quotes.. not sure, if the difference to the former behavior is different. Also, it only works in the Desktop mode of the mobile browser, or on the desktop.

What I have found is it seems inconsistent, that sometimes it works and sometimes not.