Turbomaster VNT17 Failure

I have just recently replaced the turbo on one of my cars (2005 Passat TDI/Garrett VNT17). At the time of failure it was only about 2000 miles old. The turbo failed due to a completely stuck VNT actuator - cartridge is fine. The lever wouldn't move more than an eighth of an inch. I originally tried the oven cleaner method (with turbo on car) to no avail. I drove it with the stuck VNT for quite a while as the car still had power and could almost maintain interstate speeds (with the help of a OBD tool to reset the reoccurring underboost code).

Once the turbo had been removed, I was curious about what had happened to it to make it stick so terribly, so soon in its life. Disassembled, cleaned with easy off, inspected and found some roughness where the vanes meet the walls. This is shown in the photos attached. The vanes themselves also have some of this roughness on them, though only on the interior side. When reassembled the VNT mechanism does not work.

My question to you all is what do you think caused this? Have any of you encountered something like this? I am worried that whatever conditions created this issue in such a new turbo may be eating away at the working turbo I just installed. I am pretty confident that this is not carbon buildup as I have thoroughly cleaned the surfaces with appropriate chemicals.

Do you have a larger picture?

Do you mean larger in reference to the physical size? Its larger/better quality if you use this link: https://s33.postimg.cc/dmm2iwxjf/IMG_0362.jpg

It's the same small size picture as the first post.