I lifted the plastic harness from the rubber suit and I applied some tape underneath the plastic. This ensures that no contact is made from the plastic and the rubber. Only been two days but no oil, we'll see what happens.
I know that there have been many discussions in the DX batman about their attempts but I never had the DX so I never followed the discussion. I did find it odd that all the leaks in that figure seem to come only in the upper body and nothing below where it was all rubber.
My only hope is that contact between the plastic material and rubber is creating some chemical reaction that is increasing the deterioration of the rubber. One thing though, I discovered the leak a few weeks ago when it was first discussed here and I lifted the plastic harness from the rubber and inserted regular paper in between and the oil residue did not return.
I am posting this early since it will take a month or two to see if the leaks continue and some people may want to test this for themselves or at least insert a temporary barrier to prevent further leaks and rubber deterioration.