Oda had one mistake with Ulti mask in the last chapter, and two in this one.
First with O-tama. BM took her from Usopp and put it somewhere upstairs, and Nami and Usopp ran ahead, but when she took the soul from Zeus, Oda again drew O-tama in Usopp's hands, although she only returned to them after a page.
The second is with Napoleon. Now it pierces Prometheus and Hera, now it is in the left hand, now in the right.