[1.16.4] Intermittent movement of the entity.

I need to move one entity together with another. I do this by setting the position of the second entity in the class of the first. The problem is that the second entity moves in jerks, slightly ahead of the first. If anyone knows what could be the reason, I would be very grateful for the tips. P.s. Sorry for my English.

Code from the first class, responsible for the movement of the second entity:

    private void movePart(EntityPart part)
    {
      	part.setPosition(
                this.getPosX(),
                this.getPosY() + 1.3f,
                this.getPosZ()
        );
    }

    @Override
    public void tick()
    {
        super.tick();
        for (EntityPart part : bodyParts)
        {
            if(part != null)
            {
                movePart(part);
            }
        }
    }