I have put the following file into "data/minecraft/loot_tables/blocks" of a data pack, then execute the following command

loot spawn ~ ~ ~ mine ~ 0 ~ minecraft:wooden_pickaxe{loot_table_tool:1b}

where ~ 0 ~ has a shulker_box with some item in it.

The expected behavior (in vanilla) is to summon all items in shulker_box at the current location, but in the spigot, it only summons the item in the box with a smaller slot number, won't summon the item in the box with a larger slot number (the exact splitting number varies), and a message of "An unexpected error occurred trying to execute that command" is printed.

However, the command 

loot give @s mine ~ 0 ~ minecraft:wooden_pickaxe{loot_table_tool:1b}

work as expected.