UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/61.0.3163.79 Chrome/61.0.3163.79 Safari/537.36

Steps to reproduce the problem:
1. go to https://webrtc.github.io/samples/src/content/peerconnection/pc1/
2. make a call
3. execute this in the JS console: pc1.close(); pc1.getStats().then(result => console.log(result.size));

What is the expected behavior?
the getStats call should return stats about the call even after close is called

What went wrong?
result.size is two and it only returns very basic information. The legacy stats retain old stats, see e.g. pc1.close(); pc1.getStats(res => console.log(res.result().length));

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 61.0.3163.79  Channel: n/a
OS Version: 
Flash Version: Shockwave Flash 16.0 r0

not sure what the spec currently says, at least at some point there was a "we should allow this", see https://bugzilla.mozilla.org/show_bug.cgi?id=1056433