In section 13.6 of Nakahara, the parity anomaly is in odd dimensional spacetime.
From the paper "Fermionic Path Integral And Topological Phases"
https://arxiv.org/abs/1508.04715
by Witten, the problem appears as one cannot define the sign of the path integral,
S[ˉψ,ψ;A]=∫d2n+1xˉψiD/ψ,
Z=det(iD/)=∏λ∈specλ,
because there are infinite number of positive and negative eigenvalues λ.
The number of eigenvalues flowing through λ=0 is related with the index theorem in 2n+2 dimenions.
Does the partiy anomaly appear in even dimensions?
From Nakahara's derivation, I don't see anything related with the dimension of spacetime. If this anomaly exists in odd dimensions, then why doesn't it appear in even dimensions?
I also posted my question here
https://physics.stackexchange.com/q/436841/185558