Add a scoreboard with shears being used as the criteria:

/scoreboard objectives add shear minecraft.used:minecraft.shears

Display it in the sidebar:

/scoreboard objectives setdisplay sidebar shear

This scoreboard objective doesn't increase when mining carpet with shears and the other mentioned blocks.
If you use the criteria "minecraft.used:minecraft.diamond_pickaxe" and use said diamond pickaxe to mine carpet the score for the pickaxe increases, so why wouldn't it with shears?

Another Argument on why this is a bug is that the durability decreases in both cases, so the tools are clearly being used!

I think it might be good to have a list of blocks where it does not work. For the reason that you need to have the block mined with shears to actually collect an item, but where the criteria does not tick up.

• tall_grass
• large_fern
• seagrass
• tall_seagrass
• nether_sprouts