IE9 and head.js load script twice

Using Head.js (0.9) and checking the loading of scripts from IE9, the IE9 developer's "Network" panel shows that javascripts are being loaded twice.

The first time the script is loaded with a HTTP result code of 200, after which the same script is reloaded with a result code of 304 (unchanged).

However, the script area and the script block show scripts loaded twice. This in turn makes one of the scripts (sIFR.js) dump its global sIFR object.

I suspect double loading is causing this.

Note. Chrome and Firefox work as expected.

Has anyone else seen this strange behavior?