[Crannogman]

Seems a pretty rudimentary system - the formation geometry is based on the lead ship, and changes immediately when that ship turns. Thus, ina longer formation, the lead ship's turn to the left means the column now stretches off the right.
I remember a similar pattern from Destroyer Command; I would often take my squadron through a series of formations (column, echelon, column/abreast) to keep the individual ships in the position I wanted while turning. I guess the devs never saw a reason to mess with it.