Yep, you can see the black, crusty stuff coming out from under the cup.
If you can had gone one step further and pulled the wheels apart, then you would've seen the mess that's under the cup.
Congrads for getting down to the bottom of this!
Replacing the turbo is a lot better than replacing the engine...
Looking at the non-stock bolts on the compressor housing side, this turbo has been taken apart / rebuild before?
-Ted