I've also been curious about this phenomenon, but haven't studied it in depth. I remember pointing out to my wife a few months ago that along our driveway, which is oriented East-West, the bunches along the South edge of the driveway were nearly all hanging (and plants leaning) in towards the driveway, or towards the North; away from the sun but towards the most light. Along another road we have that is oriented North-South, the plants were all leaning & fruiting again towards the road, which would be to the East and towards the most light. At another location alongside a creek, which runs North-South, the plants are laid out from the East side of the creek and those closest to that opening in the plantation made by the creek, lean & fruit toward the creek; Westerly, and towards the most available light. How steadfast is this tendency to lean and fruit toward the most available light? Pretty strong here at my place, based on my simple observations, but would need more study to prove reliably how sure this would always be.
Here you can see the many fruit bunches along my driveway leaning toward the North. There are only 2 rows seen here, spaced 2 meters apart and running East-West, but the row on the North side nearly always leans and fruits North toward the most light:
