see what? Where was it said that it was Shanks' job and not Aramaki himself transforming back?
in any functional brain that can understand images
panel 1 - ryokugyu in logia form is going to stab momonosuke
panel 2 - the haki covers the sky
panel 3 - haki hits ryokugyu and he starts reverting to human form
panel 4 - he is asking who is he source of the haki
panel 5 - he realizes the source and his body os now all human
panel 8 - ryokugyu is frozen and shaking
why ryokugyu would decide to turn human when he was going to kill momonosuke ? he did not even know who was sending the haki yet
or shanks haki nullified his powers or made him so scared he could not keep the transformation I do not now which is worse