Problem with f2py not modifying an inout array - numpy

Question

I have a fortran routine that takes 6 arrays as input, and modifies the content of the first array. The arrays are all numpys with the following flags
C_CONTIGUOUS : False
F_CONTIGUOUS : True
OWNDATA : False
WRITEABLE : True
ALIGNED : True
WRITEBACKIFCOPY : False
UPDATEIFCOPY : False
I tried declaring the array that needs to be modified as intent(in, out), also tried intent(inout), and using the inplace modifier, but in every case, once the routine terminates, the array that was supposed to be modified is not modified on the Python side. Using the -DF2PY_REPORT_ON_ARRAY_COPY=1 I also note that 5 arrays are copied. This of course creates a performance issue. What I am doing wrong?
This is the fortran subroutine
subroutine POISSONOP_GSRB(
& phi
& ,iphilo0,iphilo1
& ,iphihi0,iphihi1
& ,nphicomp
& ,rhs
& ,irhslo0,irhslo1
& ,irhshi0,irhshi1
& ,nrhscomp
& ,Mx
& ,iMxlo0,iMxlo1
& ,iMxhi0,iMxhi1
& ,nMxcomp
& ,My
& ,iMylo0,iMylo1
& ,iMyhi0,iMyhi1
& ,nMycomp
& ,Mz
& ,iMzlo0,iMzlo1
& ,iMzhi0,iMzhi1
& ,nMzcomp
& ,Dinv
& ,iDinvlo0,iDinvlo1
& ,iDinvhi0,iDinvhi1
& ,idestBoxlo0,idestBoxlo1
& ,idestBoxhi0,idestBoxhi1
& ,whichPass
& )
implicit none
integer nphicomp
integer iphilo0,iphilo1
integer iphihi0,iphihi1
REAL*8 phi(
& iphilo0:iphihi0,
& iphilo1:iphihi1,
& 0:nphicomp-1)
cf2py intent(in, overwrite) phi
integer nrhscomp
integer irhslo0,irhslo1
integer irhshi0,irhshi1
REAL*8 rhs(
& irhslo0:irhshi0,
& irhslo1:irhshi1,
& 0:nrhscomp-1)
cf2py intent(in, inplace) rhs
integer nMxcomp
integer iMxlo0,iMxlo1
integer iMxhi0,iMxhi1
REAL*8 Mx(
& iMxlo0:iMxhi0,
& iMxlo1:iMxhi1,
& 0:nMxcomp-1)
cf2py intent(in, inplace) Mx
integer nMycomp
integer iMylo0,iMylo1
integer iMyhi0,iMyhi1
REAL*8 My(
& iMylo0:iMyhi0,
& iMylo1:iMyhi1,
& 0:nMycomp-1)
cf2py intent(in, inplace) My
integer nMzcomp
integer iMzlo0,iMzlo1
integer iMzhi0,iMzhi1
REAL*8 Mz(
& iMzlo0:iMzhi0,
& iMzlo1:iMzhi1,
& 0:nMzcomp-1)
cf2py intent(in, inplace) Mz
integer iDinvlo0,iDinvlo1
integer iDinvhi0,iDinvhi1
REAL*8 Dinv(
& iDinvlo0:iDinvhi0,
& iDinvlo1:iDinvhi1)
cf2py intent(in, inplace) Dinv
integer idestBoxlo0,idestBoxlo1
integer idestBoxhi0,idestBoxhi1
integer whichPass
integer i,j
integer indtot, imin, imax
integer n, ncomp
REAL*8 Sphi
REAL*8 MyL
REAL*8 MyR
ncomp = nphicomp
do n = 0, ncomp-1
do j = idestBoxlo1, idestBoxhi1
MyL = My(0,j,0)
MyR = My(0,j,1)
imin = idestBoxlo0
indtot = imin + j
imin = imin + abs(mod(indtot + whichPass, 2))
imax = idestBoxhi0
do i = imin, imax, 2
Sphi =
& Mx(i,0,0) * phi(i-1,j,n)
& + Mx(i,0,1) * phi(i+1,j,n)
& + MyL * phi(i,j-1,n)
& + MyR * phi(i,j+1,n)
phi(i,j,n) = Dinv(i,j)
& * (rhs(i,j,n) - Sphi)
enddo
enddo
enddo
return
end
and this is how it is called on Python
GS.poissonop_gsrb(phi.data,phi.box.LoEnd()[0],phi.box.LoEnd()[1],phi.box.HiEnd()[0], phi.box.HiEnd()[1],
rhs.data,rhs.box.LoEnd()[0],rhs.box.LoEnd()[1],rhs.box.HiEnd()[0], rhs.box.HiEnd()[1],
Mx.data,Mx.box.LoEnd()[0],Mx.box.LoEnd()[1],Mx.box.HiEnd()[0], Mx.box.HiEnd()[1],
My.data,My.box.LoEnd()[0],My.box.LoEnd()[1],My.box.HiEnd()[0], My.box.HiEnd()[1],
Mz.data,Mz.box.LoEnd()[0],Mz.box.LoEnd()[1],Mz.box.HiEnd()[0], Mz.box.HiEnd()[1],
DInv.data,DInv.box.LoEnd()[0],DInv.box.LoEnd()[1],DInv.box.HiEnd()[0], DInv.box.HiEnd()[1],
L[0], L[1],H[0], H[1], whichPass,
)
Note that the last dimension of the arrays is inferred and thus not specified.