fill command stops working if i go lower than y-1 of player's relative position (~ ~-1 ~)

for some reason, whenever i make a function/command block fill an area that goes below a players y-1, it just doesnt work at all. no output either. this really fucks up my dynamic light system 😭 
execute at @a run fill ~2 ~-2 ~-2 ~-2 ~2 ~2 air replace light[level=13]
execute at @a[tag=holdingHope] run setblock ~ ~1 ~ light[level=13]

the light appears, but doesnt clear itself.