Each time I log into my world, I notice that a lot of jungle leaves I placed disappear, and a few of them leave jungle saplings. And the problem is that when I place the leaves down, its default state is persistent: true, which I assume is the new way of saying the leaves don't die naturally. But when I log back in, all the leaves have the state persistent: false, and that's why all my leaves are going away. I don't know if it's just with Jungle Leaves or all leaves, and I don't know if this issue occurs when I exit the world or when I log back on, but here are images that show before and after I exit then enter the world:

Before I exit the world:

Once I re-enter the world: