falling_block entity disappearing to late

falling_block enitity disappearing to late

What I expected to happen was...:
falling_block despawning when reaching Time:0

What actually happened was...:
falling_block dropping when reaching Time:600

Step to Reproduce:
/summon minecraft:falling_block ~ ~1 ~ {Time:-200,NoGravity:true,BlockState:

{Name:"minecraft:sand"}

}