Big video latency between ios9 and firefox and chrome!

My test environment:
- Access web of http://demo.openwebrtc.org:38080/ on Iphone or chrome.
- chrome or firefox on PC.
- iPhone 5 with iOS9;
- Framework: using myself build based on cerbero on 24 oct. or @casey 10.10.2015 build: https://drive.google.com/open?id=0B49chjTf6eU1SWJKYlJ6WWJqZTA
- build on SimpleDemo on xcode 7.0.1 based on EricssonResearch/openwebrtc-examples#125 @stefanalund

Step:
- iphone 5(iOS9) and chrome load the test page of http://demo.openwebrtc.org:38080/
- select audio and video on iphone 5(iOS9) and chrome, then 'join'. all device an see local video.
- select 'call' on iphone 5.
- wait about 0.5 seconds, on chrome/firefox, we can see black video for remote.
- wait about 2~5 seconds, on chrome/firefox, we can see remote video.
- wait about 10~30, sometimes we can see the first remote video on iphone. sometimes always cannot see remote video on iphone.
- even when we can see the first frame remote video on iphone, but we cannot see the remote video again(cannot see real video. ).

Question:
- 1, Anybody has pay attention to this issue? or enly my test environment issues?
- 2, Has anybody done some tests between iphone and chrome/firefox.

Note:
- When I setup the test page of on my local LAN, I have gotten the same result. so the latency is not networks problem.
- I have tracked the offer/answer, the video should be using VP8.

Start by reproducing the issue with the stated iPhone 5/iOS 9, Chrome or Firefox, SimpleDemo, and the demo page or local LAN setup. Compare the offer/answer and VP8 video behavior during the delayed or missing remote stream. Done means identifying whether the failure is in the environment or framework and documenting a confirmed fix or reproducible diagnosis.

Written by the indexing model from the issue text.