I found Clone Clock also triggered this bug.
The wool colors represent the chunks.
The two command_blocks have the same command, /clone ~ ~1 ~ ~7 ~1 ~7 ~ ~ ~.
The lower command_block clones 63 * air and 1 * command_block every tick, and no redstone_block is cloned.
I think maybe this bug does not depend on the block types.
I confirmed the same result with the following commands.
/fill ~ ~-1 ~ ~7 ~-1 ~7 redstone_block
/fill ~ ~1 ~ ~7 ~1 ~7 stone
Regardless of mobGriefing, Villager's CanPickUpLoot is always true and cannot be set to false.
If mobGriefing is false, Villagers cannot pick up bread because the gamerule precedes their CanPickUpLoot.