What direction must one stir molten chocolate?
I see enough here: Rheological measurements of chocolate quality:


non-Newtonian liquid
non-ideal plastic behavior
time-dependent behavior
Thixotropic/non-thixotropic transition


To make me think that changing the direction in which you are stirring melted chocolate might easily cause changes in the properties of the melt that take a while to settle down.
However, if there were a "clockwise in the northern hemisphere and counterclockwise in the southern hemisphere" rule, or some such, that rule should appear in the cited tech literature. It does not, so there probably is no such rule.