I'm seeing intermittent H28 warnings in my router logs and on the dashboard.
The best description of what you are seeing can be found here. It is likely that your app is waiting for the full request to be sent before your app will process it. However, this never happened because the value of the
Content-Length header was larger than the amount of data sent, so the app continued to wait. After waiting 55 seconds for the additional data to be sent, the connection was terminated.