Looks like the gasket is starting to go away. If you notice, the bolt hole goes through the bearing housing. Once the gaskets starts to degrade, oil can and will travel up and out the bolt hole, as well as past the gasket. Might want to get a new gasket from one of the reputable turbo vendors and glue it on. Pretty common. I advise using care when moving the factory oil return line around while changing the gasket. Excessive bending of that tube can and will cause a crack over time. Just the smallest crack in that tubing can lead to a huge oil leak.
HTH
Patrick