I have had similar results with my Nikon N80. After being told in no uncertain terms that is strictly was impossible to shoot HIE in my camera, I loaded it up anyway. As Steve says, only about 1/2 the sprocket hole appears to be affected by the IR sensor in the camera. I have seen no fogging whatsoever in the film. I have experienced no problem with the IR sensor on rewind.
If truth be known, I have only shot "near-IR", using a dark red filter, not the full IR filters. I doubt it would make much of a difference.
Of course, this discussion is pretty much academic, as the supply of HIE is rapidly dwindling. I've got two rolls in my freezer. There are another half-dozen in my local camera shop. (but at approaching $20 CDN including taxes, I'm not that desperate to hoard them)
Cheers,