Fullbacks (LB/RB) stay back while attacking

Same here. Doesn't look like roles matter too, whether it's inverted, attacking, fullback/wingback, they all stay in the same position and only just move into the desired zone, once you get close to the final third. And if you pass backwards they rush to defense and form a back four. Even adjusting the sliders to have fullbacks positioned as high as possible doesn't help.