There is two things going on there.

First if you look closely you can see holes in the spud. This is insect damage, likely caused by a wireworm (larval form of a clickbeetle species.)

Second is a physiological damage in storage/shipping causing the black color. This is not blight or another fungus, but the tubers reaction to suboptimal storage condition (not enough O2).

https://www.journals.uchicago.edu/doi/pdf/10.1086/333609