Try this, go to Google and type in "eggzackly this".
Two results not containing "eggz" at all.
Two results containing "eggzackly<punctuation>this"
Two results containing "eggzackly" but missing "this".
Google Search is broken. It no longer does what it's directed, it just takes a guess. I suspect part of this is because someone decided that "no results found" was the worst possible result a search engine could give.
Googling that with the brackets I get results containing "eggzackly this" ranked 3, 4, 6 (your comment) and 7 whereas the others contain just eggzackly (or with the 'this' preceded by punctuation as you mention).
Therefor I don't see how your last sentence is the explanation (there are results), I've also happened to land on no results found sometimes with overly precise quoted queries (for coding errors mostly IIRC). But it is annoying that it doesn't seem stricktly enforced even when you want it to.
Two results not containing "eggz" at all. Two results containing "eggzackly<punctuation>this" Two results containing "eggzackly" but missing "this".
Google Search is broken. It no longer does what it's directed, it just takes a guess. I suspect part of this is because someone decided that "no results found" was the worst possible result a search engine could give.