Sulfur Cubes don't drop their block when killed if the block was added with a command

If you manually give a Sulfur Cube a block and kill it with commands (/kill, /damage) the block gets dropped.

If you give a Sulfur Cube a block via a command and then kill it, the block is not dropped.

Reproduction Steps:

1. Summon a Sulfur Cube

2. Use a /data command to add a block:

   /data merge entity @n[type=minecraft:sulfur_cube] {equipment: {body: {count: 1, id: "minecraft:light_blue_wool"}}}

3. Kill the Sulfur Cube

You will see how the block is not dropped.

Repeat the steps except instead of adding the block with a command, click a block on the cube and then kill it. You will see the block drop.

Expected Result: For the block in the cube to drop no matter how it was added.

Actual Result: The block in the Sulfur Cube is not dropped if it was added with a /data command.