Rotating images, with fade: first one appears, briefly, then snaps to second. Rest OK

Hi
Great Forum - great theme.

I am using WordPress 3.2.1. and Atahalpa 3.6.7

I have 4 header images set to rotate (8 seconds) and fade (2 seconds).

However when the blog first loads, one of the images appears for about 1-2 seconds and then snaps (not fades) to the second image.

After that all works properly. I am viewing it in Firefox 6.0.2.

Unfortunately the initial load looks a bit naff.

Any ideas how to fix this please? Thanks, Phil