/stat command does not track for non-player entities

The /stat command does not track for non-player entities.
Unknown why this is happening, although it might be user error but I am pretty sure I'm doing this correctly

Commands used
/scoreboard objectives add check dummy
/stats entity @e set AffectedBlocks @e check
/execute @e[name=step] ~ ~ ~ fill ~ ~2 ~ ~ ~3 ~ redstone_block
/scoreboard objectives setdisplay sidebar check

any entities named step will fill blocks with redstone, but the amount of blocks placed is not tracked in the sidebar.

any command blocks used are running.
I have tried breaking the blocks placed also, but that does not fix the problem.