This is a Suspect A01 from Amazon. See:
https://www.bobistheoilguy.com/foru...m-a01-or-am-i-being-paranoid#Post4984055
The discoloration appears to be some sort of oil, probably a corrosion inhibitor.
Examination under magnification it appears the line between the diamond and the dot may be a tool skip or drag.
I believe this filter is genuine.
https://www.bobistheoilguy.com/foru...m-a01-or-am-i-being-paranoid#Post4984055
The discoloration appears to be some sort of oil, probably a corrosion inhibitor.
Examination under magnification it appears the line between the diamond and the dot may be a tool skip or drag.
I believe this filter is genuine.