There's a problem when the touchstart event is binded on an element of a page included Redactor (even if the element is outside the Redactor iframe, even if the binded function does nothing, no matter if the way to bind this event uses jQuery or the JS addEventListener command).
I think I ran into this bug before (pre-1.2 beta release) as I had a workaround in for an iOS bug relating to zoom levels. I spent a while debugging it then and didn't really get anywhere -- I couldn't isolate it. Even removing the event listener after firing didn't sort it.
I will make another attempt over time, but it may not be something that we can completely sort. There's pretty clearly an iOS browser quirk in here.