Video quality doesn't recover when going from area with poor signal reception area to good one

[Anton Kuzmin]

We have identified an issue in webrtc when using either web application in chrome or iOS app (haven't tried other platforms). The steps to reproduce:

1. Start a webrtc application on a smart phone
2. Disable 4g
3. Go to area with poor network signal (3g with 2 bars)
4. Start publishing video via webrtc (one way streaming without subscribing)
5. Stay in the area for about 1 minute. Notice that receiver will get video of small size and very poor quality (pixelated and / or chunky).
6. Go to area with good signal (3g with at least 4 bars)
7. Stay there for about 1 or more minutes

Expected: video quality improves and video frame size increases

Actual: video quality and frame size stay the same

Chrome 59, 60

WebRTC M69, M60 in iOS

Did somebody experience something like that? Am I missing something in configuration?