/cgetdata for entity missing attributes

[Dark-Phoenix-01]

When performing /cgetdata command on some entity, very often lot of the attributes are missing. For example when checking a leader zombie data, here's the comparison.

NBT data from /data get command

Zombie has the following entity data: {DeathTime: 0s, OnGround: 1b, LeftHanded: 0b, AbsorptionAmount: 0.0f, IsBaby: 0b, Invulnerable: 0b, Brain: {memories: {}}, Rotation: [37.98845f, 0.0f], HurtByTimestamp: 0, ArmorDropChances: [0.085f, 0.085f, 0.085f, 0.085f], HandDropChances: [0.085f, 0.085f], CanBreakDoors: 1b, attributes: [{base: 0.23000000417232513d, id: "minecraft:generic.movement_speed"}, {modifiers: [{amount: 0.5861681693676828d, id: "minecraft:leader_zombie_bonus", operation: "add_value"}], base: 0.03319467453311349d, id: "minecraft:zombie.spawn_reinforcements"}, {modifiers: [{amount: 0.030858318074534607d, id: "minecraft:random_spawn_bonus", operation: "add_value"}], base: 0.0d, id: "minecraft:generic.knockback_resistance"}, {modifiers: [{amount: 2.6414639806218307d, id: "minecraft:leader_zombie_bonus", operation: "add_multiplied_total"}], base: 20.0d, id: "minecraft:generic.max_health"}, {modifiers: [{amount: 0.007293420674694934d, id: "minecraft:random_spawn_bonus", operation: "add_multiplied_base"}], base: 35.0d, id: "minecraft:generic.follow_range"}], InWaterTime: -1, ArmorItems: [{}, {}, {}, {}], Air: 300s, HandItems: [{}, {}], UUID: [I; -1877554765, -760133020, -1763644339, 521401789], FallDistance: 0.0f, DrownedConversionTime: -1, Motion: [0.0d, -0.0784000015258789d, 0.0d], Fire: -1s, Pos: [231.74624474615766d, -55.0d, -97.8144790014777d], CanPickUpLoot: 0b, Health: 20.0f, HurtTime: 0s, FallFlying: 0b, PersistenceRequired: 0b, PortalCooldown: 0}

Data from /cgetdata command

 Zombie has the following entity data: {DeathTime: 0s, OnGround: 1b, LeftHanded: 0b, AbsorptionAmount: 0.0f, IsBaby: 0b, Invulnerable: 0b, Brain: {memories: {}}, Rotation: [37.96875f, 0.0f], HurtByTimestamp: 0, ArmorDropChances: [0.085f, 0.085f, 0.085f, 0.085f], HandDropChances: [0.085f, 0.085f], CanBreakDoors: 1b, attributes: [{base: 0.23000000417232513d, id: "minecraft:generic.movement_speed"}, {base: 20.0d, id: "minecraft:generic.max_health"}], InWaterTime: -1, ArmorItems: [{}, {}, {}, {}], Air: 300s, HandItems: [{}, {}], UUID: [I; -1877554765, -760133020, -1763644339, 521401789], FallDistance: 0.0f, DrownedConversionTime: -1, Motion: [0.0d, -0.05339160692480155d, 0.0d], Fire: -1s, Pos: [231.746337890625d, -55.0d, -97.814453125d], CanPickUpLoot: 0b, Health: 20.0f, HurtTime: 0s, FallFlying: 0b, PersistenceRequired: 0b, PortalCooldown: 0}

Now, I understand some data may not be visible due to permission issue, but there are some data that is visible but not pulled by the command. Like max health of the zombie which I know is visible because I have mob health mod which correctly shows max health as 73.

[xpple]

I also see the max health in the result of cgetdata, am I missing something?