I've been trying to use smaller ships to provide point defense for my missile kiting cruiser, but every time I get close to an enemy the pd ships break formation and close to weapons range (and then get blown to bits). I've tried using default formations (line, wedge, reverse wedge) and creating custom ones, but nothing seems to stick. The formations work fine out of combat, they only break when closing with an enemy.
Not sure if this is a bug or just me not understanding formations. Any ideas what I'm doing wrong? Ideally the pd ships would hold positions just off the front corners of my missile cruiser.