Dash doesn't adapt to low bandwidth

Created by: Ismael

Environment

• The MPD passes the DASH-IF Conformance Tool on http://dashif.org/conformance.html
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream
• The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
• The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on

• Link to playable MPD file: https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps.mpd
• Dash.js version: 2.7.0
• Browser name/version: Chrome 66.0.3359.117
• OS name/version: Linux Debian

Steps to reproduce

1. In developer tools, Network, create a 1Mbps setting
2. Load the MPD in the reference player
3. Reload / play until it decides to start with a bitrate above 1Mbps
4. Limit the network to 1Mbps

Observed behaviour

The player won't step to a lower bitrate, even though the buffer is empty almost all the time.