Two months or thereabouts. No sign of oil. I also had a DX02, which never exhibited any oil either.
I've worked with polyurethanes and silicones for many years now. If the rubber mix is bad, it usually shows up pretty quickly as oil patches like beads of sweat.
I think there is possibly a different reason for this. Hot Toys uses a lubricating oil to getting the rubber suit on. Once the suit is on that oil has no place to go, but sit there. If the oil is excessive it will eventually leak through any points where the true type body touches the suit and pressure is applied, like around the belt area.
A suggestion - and Ill be doing the same if mine starts leaking - remove the rubber suit. Wash the true type body and suit with liquid soap to remove all of the lubricating oil. Once it is fully dried, use talc to aid getting the suit back on.
If it is the lubricating oil causing the issues, this will certainly help. Certainly worth a shot.