Just discovered this on my iPhone 6. When I turn on Assistive Touch, the Siri circle is greyed out (see pic). This means that when I touch the Siri circle, nothing happens. When I then turn Assistive Touch off and back on again, the Siri circle then becomes active again?! I have tested this on an iPhone 5 and it does NOT experience the same issue. This happens EVERY time I turn on my iPhone 6. The Siri circle is in-active UNLESS I turn Assistive Touch off and then back on. Do you think I should report this on the Apple Bug Reporter website?!