In short, the following worked for us:
Change this:
var playerResource:URLResource = new URLResource(url);
to this:
var playerResource:StreamingURLResource = new StreamingURLResource(url);
playerResource.streamType = StreamType.LIVE_OR_RECORDED;
In detail, we know that OSMF 2.0 did not change between Flash 11.6 and Flash 11.7. However, it seems as though the interpretation of the default value of streamType
did change, possibly by accident. Flash 11.7 treats the default as though it is a "live stream" and does not cache.
By specifying streamType
explicitly, things go back to normal. There is no "Pragma: no-cache" in the HTTP request. Our app calls out for the video once, and then it is cached. This fix also works in the original env, Flash 11.6.