Yes, those sections are dead or dying. Cut them off and let the good wood thrive.

If you see mushroom anywhere it is sustained by a vast mycelium weblike network that is suffused through a medium like soil or in this case, a dead branch on your tree, the fungus probably arrived after the branch died, but may spread to the healthy parts of the tree, best to remove what your can, the tree will naturally compartmentalize its healthy parts like a spaceship

White fungus (or lichen) on my cherry tree. Is it bad?