Using the latest Puppeteer (2.0.0) an issue came up, which seemed suspicious to me. I wanted to do a file upload and intercept that request. However, the POST request data didn't show up in the interception.
Next up, I tried to do this within the latest Chrome Stable
(78.0.3904.70) on macOS 10.15 and there didn't show up any data inside the dev tools. The data itself however is showing up properly (you could use
https://codesandbox.io/s/fervent-http-c24v7 as an example, which does a POST to
post-echo.com/post - this in turn replies with the submitted data). When doing the test with the before mentioned URL, I see, that the data is actually being transmitted.