Possible error in figure in Ch12 on page 421

[olivertomic]

To me it seems there is an error in point 4 (error term of the hidden layer) in the figure regarding the derivative of the activation function (after the elementwise multiplication operator) . It says in the numerator: derivative of phi(a), while I would have expected phi(z). For the denominator correspondingly: it says derivative of a, while I would have expected derivative of z. The same equation in the same figure in the second edition of the book looks right to me.

The same equation looks correct on page 418 in the third edition, although z should be bold.