From Command line this works just fine:

setblock ~ ~ ~ chest{Lock:"Player's Key",LootTable:"hard:chests/chest_1"}

but when running it in a datapack as a tick function like so:

execute as @e[type=armor_stand,name=chest,tag=spawnchest,limit=1] at @s run setblock ~ ~ ~ chest{Lock:"Player's Key",LootTable:"hard:chests/chest_1"}

the commands run everything right except the Loottable. it spawns chest and when I open it with the key there is no loot_table applied. don't understand : bug I don't know