When using a bought texture pack, new and old, it doesn't change textures of items and blocks all the time. A lot of them, don't change to the texture pack you select on xbox.

After repeated tries and buying texture packs that have been just released and some that are a but older. Non of them change the textures for for example cobblestone, stone and all their related blocks. And not to forget, they also dont update any or almost any items. This seams to mostly, but not only happen to items changed during or after the village and pillage update. But not to any items released during or after. Like how the pillagers remain changed after changing the texture pack.