Package: pari
Version: 2.7.6

I get :

? K = nfinit(y^2+1); L = rnfinit(K, x^2-y);
? L.pol
%2 = x^2 – y

But according to 3.6.133 in the Pari / GP User Guide Version 2.7.6 this should be the result :

? K = nfinit(y^2+1); L = rnfinit(K, x^2-y);
? L.pol
%2 = x^4 + 1

And in Version 2.5.4 this is the result !

I use the Windows Version gp64-readline-2-7-6.exe .