I had an issue where practically everything on my page was set to push and when I tried moving a repelling image, xara freaked out and after a while, came up with a warning. I guess it hit an infinite loop where moving one object had a knock on effect on other objects until it also had a knock on effect on the object I just moved etc. But at least xara realized and gave me a warning but I guess you could have a similar issue?
I went back and removed some unnecessary push positionings and it has been okay since.