Version: 53.0.2785.0
OS: MacOS

What steps will reproduce the problem?
(01) Download this node app: https://f.surma.link/nh2.zip
(02) Start it using `node index.js`
(03) Open Canary
(04) Open DevTools and set network throttling to “Good 2G”
(05) Go to https://localhost:8080
(06) Wait 5s to see a picture load *progressively*
(07) Restart the node server
(08) Disable network throttling
(09) Go to https://localhost:8080/index.html?throttle=true
(10) Wait 5s to see a picture load *instantly*

The app serves a page that loads an image after 5 seconds. That image is sent using HTTP/2 push with the initial requeust.

If we throttle using DevTools, the image is loaded progressively even though it has been fully pushed by the server.

If we throttle server-side, the image appears instantly as it has been fully pushed by the server.

Expectation:
In both cases the image should appear instantly.