Looking at the plotband.f90 code, jumps are allowed:
IF (dxmod > 5*dxmod_save) THEN
!
! A big jump in dxmod is a sign that the point k(:,n) and k(:,n-1)
! are quite distant and belong to two different lines. We put them on
! the same point in the graph
!
kx(n)=kx(n-1)
Cheers,
Vahid