This may not be a real bug, but maybe a graphical error or I just would like to advise to fix this issue.
I noticed that when activating the entities hitbox (f3 + B), if you look at the blue line, i.e. the direction in which the entity is looking, the phantoms have it backwards: if they look down the blue line it directs upwards and vice versa. So I would like to ask if  is it possible to redo the animation with the blue line that goes in the direction in which the phantom is looking (this might seem strange if we talk in the field of command blocks).