As John predicted, Mitch did swap out the IRF-6 unit, but the problem persists.

I've reprogrammed my T2 with parallel pages for IR and RF commands so that I can use IR when I'm sitting in front of my equipment and RF when I'm elsewhere. This is not exacty an elegant solution, but it may be the best I can do.

If this is a common problem, as John suggests, maybe I should try a third unit. I'm also thinking of trying a different antenna. Any thoughts?