In 1.21.50.28 Preview, the texture of nether bricks has been updated in texture file. However, due to spelling error, the new texture is unused actually.
Code Analysis:
The texture definition of nether bricks from /resource_packs/vanilla_1.16/blocks.json:
"nether_brick": {
"textures": "nether_brick",
"brightness_gamma": 0.80,
"sound": "nether_brick"
}The file path of new texture is /resource_packs/vanilla_1.21.50/textures/blocks/nether_bricks.png. The new texture is not named as nether_brick.png, causing unused texture.
How to Fix:
Changing the file name of new texture from nether_bricks.png to nether_brick.png, or changing the texture definition from nether_brick to nether_bricks will resolve this issue.
Sorry, i don't notice that this issue has been reported. It is a duplicate of MCPE-188200.