(I first experienced this this in a Realms world I share with a friend, but I don't think it just effects Realms. I have tested this on other worlds, and it seems to be the same case. Very little to none sapling drops.)

When chopping down Jungle Trees, then waiting for the leaves to despawn and drop saplings, most will either drop zero saplings, or just 1. Other trees drop a good amount of saplings, but I've been trying to farm Jungle trees for hours total now in a realms world I share with my friend, and I was only able to plant about 6 trees total after about 30 minutes of it. Then I couldn't even keep those trees up, because once I chopped them they wouldn't drop saplings to replant them.

I don't know if it's because the sticks that drop are taking up their drop rate, or what.. But other trees are fine even with dropping sticks. 

The Jungle Tree just won't drop saplings enough to replant more, or use them. Please fix this.

I want to create a treehouse with a 2x2 Jungle Tree, but the saplings just won't drop enough. I've never seen it this bad. It's definitely a bug.