Weird behavior when updating npm. What don't I know?

Question

npm

I installed the recommended NodeJS-6.10.2 (*.msi) under Windows, rightly believing that it does not contain up-to-date npm. I put the latest (that is, the latest) npm globally, taking the command from the npm docks.
The idea was to install the latest npm
npm install [email protected] -g
npm -> C:\Users\Ivan\AppData\Roaming\npm\node_modules\npm\bin \npm-cli.js
C:\Users\Ivan\AppData\Roaming\npm
`-- [email protected]
...
Reduced tree output with ellipsis.
And now, the drum roll. Understanding on what crutches and how everything is sometimes crooked from the inside (learned from bitter experience), I do
npm update
And - bingo, I am met with this conclusion:
╭─────────────────── ────────────────────╮
│ │
│ Update available 4.4.4 → 4.5.0 │ │
Run npm i -g npm to update ──────────────╯ npm i -g npm C:\Users\Ivan\AppData\Roaming\npm\npm -> C:\Users\Ivan\AppData\Roaming\npm\node_modules\ npm\bin\npm-cli.js C:\Users\Ivan\AppData\Roaming\npm `-- [email protected] I repeat: npm update And now, of course, nothing. Those. in fact, the latest tag does not work, while there are no special reservations in the docks of the install command about this. Either this is someone's oversight, or I misunderstand something. And if I misunderstand something, then what?