According to an article in EMT Worldwide, it’s not uncommon to find lead-free fillet tears in plated through hole joints. The article presents photos that show two examples of these phenomena, both optically and by using real-time X-ray inspection.
According to the article, the images show a typical example found on the surface of the solder joint after wave or selective soldering. It can also be seen on intrusive reflow joints when solder paste is used to reflow and form a connection with through hole parts. The X-ray image shows visible evidence of tearing on joint surface and just below the surface.
The article notes that tin/copper and tin/copper/nickel do not seem to feature this defect. The article also notes that there is no evidence currently that this has any impact on the reliability of the solder joints.