Iron doors disappear from cloned blocks

When using the clone command to clone blocks that include iron_doors (especially two iron doors next to each other), the cloned copy is sometimes missing some or all of the iron doors. The more blocks in the clone command, the more likely the clone will be missing doors. To make it easier to describe and reproduce the issue, here are some step by step commands to repeat the bug:
/fill ~-5 ~-5 ~-5 ~5 ~5 ~5 iron_block
/fill ~-4 ~2 ~-4 ~4 ~2 ~4 sealantern
/fill ~-4 ~ ~-2 ~4 ~1 ~2 air
/fill ~-4 ~ ~-4 ~4 ~1 ~-4 air
/fill ~-4 ~ ~4 ~4 ~1 ~4 air
/fill ~-4 ~ ~-2 ~4 ~ ~-2 stone_pressure_plate

/setblock ~-4 ~ ~-3 iron_door 3
/setblock ~-4 ~1 ~-3 iron_door 8
/setblock ~-3 ~ ~-3 iron_door 3
/setblock ~-3 ~1 ~-3 iron_door 9

/setblock ~-1 ~ ~-3 iron_door 3
/setblock ~-1 ~1 ~-3 iron_door 8
/setblock ~ ~ ~-3 iron_door 3
/setblock ~ ~1 ~-3 iron_door 9

/setblock ~3 ~ ~-3 iron_door 3
/setblock ~3 ~1 ~-3 iron_door 8
/setblock ~4 ~ ~-3 iron_door 3
/setblock ~4 ~1 ~-3 iron_door 9

/setblock ~-4 ~ ~3 iron_door 1
/setblock ~-4 ~1 ~3 iron_door 8
/setblock ~-3 ~ ~3 iron_door 1
/setblock ~-3 ~1 ~3 iron_door 9

/setblock ~-1 ~ ~3 iron_door 1
/setblock ~-1 ~1 ~3 iron_door 8
/setblock ~ ~ ~3 iron_door 1
/setblock ~ ~1 ~3 iron_door 9

/setblock ~3 ~ ~3 iron_door 1
/setblock ~3 ~1 ~3 iron_door 8
/setblock ~4 ~ ~3 iron_door 1
/setblock ~4 ~1 ~3 iron_door 9

/clone ~-5 ~-5 ~-5 ~5 ~5 ~5 ~20 ~-5 ~-5
/tp ~25 ~ ~