I was able to get staining on a lc200n muleteam, worse than any reports of lc200n knives ive seen. The mule teams may have had some issues though. Ive also seen rust looking spots on a caribbean but most scraped off with the fingernail. The other spots came off with a bit more elbow grease.
Theres alot of random evidence thats hard to piece together. My native salt has been going through the ringer lately and has no issues whatsoever. I had it in the gulf on Sunday, the day after Nestor, it was wet all day in my boardshort pocket and on the boat. It did not recieve cleaning and is still holding up to the level of rustproofness that my h1 salts exhibit. So I dont think the water chemistry has changed.
Im sure Lance will chime in but through random threads and evidence it seems as though lc200n can stain through external contamination with other materials that its in contact with.
I really want to do a torture test in the future of several of my lc200n knives to see if I can begin to pinpoint certain variables that might contribute to how lc200n reacts to this type of stuff.
Is the datecode on your box DR (?) or later. If its before this then its a non cqi version that has a steel detent ball. This can rust.
The other issue. How was ot carried? Was it in contact with other metal? Was there a way the blade could have been contaminated?
Have you tried cleaning it yet? There is a big difference between surface contamination and pitting. How is the edge on it? Any knife that truly rust should have rust forming on the edge as well.
If it is a cqi version then I would say it looks like contamination to me. Possibly from the factory, or being carried not sure. Any of the tooling used in the assembly process could have just been used on a tool steel and left trace amounts of iron and carbon on the surface of the blade. I would say clean it and see if it comes back.
If it comes back then there is a bigger issue.