Some copper block variants and polished block variants have a shading mistake in their texture, within the lines that indicate the chiseled separation between the blocks there is a highlight pixels that should be a shading pixels instead. (I attached some screenshots for the better understanding of the problem and a texture pack with fixed textures)
list of blocks affected:
All variants of copper_block
All variants of chisheld_copper
All variants of copper_bulb
All variants of copper_grate
polished_andesite
polished_diorite
polished_granite
polished_deepslate
polished_tuff
quartz_block
lapis_block
chiseled_nether_bricks
I've updated the issue to include polished block variants.