Arm IK BREAKS when spine IK BENDS

Hi All I created simple Arm IK using the First Person template. This works well but as soon as I add some spine IK so I can crouch or look around corners. it breaks
what actually happens is the end effectors no longer line up with the controllers they get an offset. and the offset gets worse the more the back bends.
all works again if I straighten the back.

for the arms and spine I’ve tried both “FABRIK” and “TWO Bone IK” they all result in the same strange behaviour mentioned above.

any remedy or ideas would be greatly appreciated,


Ive been stuck on this one for two days. and may have found the answer.
Ill post so others who have same problem can benefit .
order seems to be very important so if you do the spine first then arms. it seems to work. it no longer gets the offsets.
thanks .