Or spray drift from someone spraying docks
Yep looks very like spray damage lost 2 acres of PB 2 kerspink seed cropGood point, potatoes desperate things for herbicide damage.
Sulfonylureas cause star-like cracking. These don't affect viability of daughter tubers
Glyphosate does affect viability of daughter tubers and can be symptomless although cracking can occur at high doses
Aminopyralid/clopyralid can cause tuber cracking and uneven growth. I don't know if they affect daughter tubers.
Really difficult to be sure sometimes as insufficient tank washing can lead to widespread damage as opposed to drift that is confined to proximity of treated grass or cereals.