Hello dear CreativeCrash members 
going through some misery 
I am currently working on an assignment , trying to make some fix shapes for this character's shoulder with deadlines on my head with a software as unpredictable as Maya (maybe cause i'm doing something wrong). I am experiencing a problem , which is comprised of 2 sub-cases which have their good and down-sides but ultimately do not complete the rig to the extent needed .
...You are looking at the main mesh , the subtractive/corrective target mesh which is set to -1 , and the main blendshape which is set to 1 in the blendshape node within the inputs of the main mesh .
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Case 1)
I seem to be getting this aweful distortion of my fix shape when i rotate the global scale . The blendshape is set to parallel deformation order . The blendshape itself works fine until i rotate the master control of the whole rig . They told me to change the deformation order , and so I did in case 2 ...
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Case 2 ) I set the deformation order of the shoulder to 'front of chain' , or in other words , under the skincluster . The weird deformation when i rotate the whole rig seems to have stopped . But this time , the blendshape itself is not shaping properly ...it pops into this strange shape when i set it to front of chain .
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What i already have considered and tried as a solution but unsuccessful 
:
a) I didn't freeze transforms , center pivot , delete history , on any of the target shapes .
b)I've tried removing the blendshape and subtractive shape from all parents and leave them independent in the outliner .
c)I've tried exporting weights , detaching skin , deleting history on mesh , then importing weights and adding blendshape .
d) All the blendshapes have a local settin of origin .
e) stripping down the whole rig to joints to see if it's my rig setup which is causing the wrong distortion of the blendshapes .
f)Recreating the Blendshapes and the corrective shape .