The alignment of hypothesis 2 against the backbone cannot be considered an error if we consider only these two translations; nevertheless, when added with the alignment of another hypothesis, it produces the low-quality CN in Figure 1b, which may generate poor translations like "he bought a laptop laptop".
the transition from i to i is in fact composed of the first transition from i to δ(i, k) and the second transition from δ(i, k) to the null state at i.