The last bug I had was another arity mishap. Suppose you have a definition f = (h = g f;x h x), than that is equivalent to, in my setting, f = ( h x h x)(g f). Since arguments are reduced to normal form, it will reduce f ad nauseum since, believe it or not, it has arity zero in my setting.
Is it a bug, or a feature? Since it has an easy fix, I am inclined to call it a feature.