Live stream freezes after bitrate change : Audio remains

Question

I've setup a very simple OSMF test player but there appears to be an issue when certain bitrate switches occur with no errors. The video just feezes, but you can still hear audio in the background.
Some details:
- We're currently using OSMF 2.0, and the Flex 4.9.1 sdk and streaming an rtmpt stream.
- For the encoding, the keyframes are 3 seconds apart
- It appears that setting the buffertime above 4 seconds will sometimes make the issue even worse
Encode settings:
Stream 1 640x360    1000 kbps 30fps 3s kf  96 kbps audio
Stream 2 640x360    700 kbps 30fps  3s kf  64 kbps audio
Stream 3 640x360    440 kbps 15fps  3s kf  64 kbps audio
Stream 4 320x180    240 kbps 15fps  3s kf  32 kbps audio
It appears that when we play the stream through an ooyala player (which does not seem to use OSMF), these issues go away.
Here is a very bare bones implimentation we're using to isolate the issue:
http://pastebin.com/esWNCEfr
I was able to replicate the issue only once using the player at OSMF.org:
http://osmf.org/dev/2.0gm/debug.html?src=
Here are the sequence of onNetStatus events when it freezes:
***** onNetStatus ****** :NetStream.Play.Reset
***** onNetStatus ****** :NetStream.Play.Start
***** onNetStatus ****** :NetStream.Buffer.Full
***** onNetStatus ****** :NetStream.Buffer.Empty
***** onNetStatus ****** :NetStream.Play.Transition
***** onNetStatus ****** :NetStream.Buffer.Full
***** onNetStatus ****** :NetStream.Buffer.Empty
***** onNetStatus ****** :NetStream.Buffer.Full
***** onNetStatus ****** :NetStream.Play.Transition -- Frozen - still hear audio
***** onNetStatus ****** :NetStream.Play.Transition -- Still Frozen.

Answer 1

I working a little bit on my problem.
I put an text area in my script to see which stream is taken.
I slow down the bandwith to 100, 200 and 350 kbps and - surprise surprise only the 100 kbps stream was taken by my app.
Nobody any idea what the problem can be?
Regards,
Daniel