No, both fleets aimed to hulls for the whole battle! We noticed the "auto sail-aiming" effect looking at the battle log, for example:
"32. Neptune shot at Royal Oak's Rigging. Hdt:1,Dice:4 (Guns:1) Damage: 1 Crew"
The bug was "on" for the first 14/20 turns, 100% of the salvo was aimed to riggings, then it suddenly expired... even if sometimes (like in turn 32 -see above-) it resurfaced looking for vengeance!
