Duplicate of:
MC-156133
MC-165077
MC-174107
MC-180580
MC-181020
MC-195061
MC-208380
MC-216722
MC-235456

Summary: The jungle unergrowth is made of jungle logs and oak leaves.
THIS IS A BUG, BECAUSE ON BEDROCK EDITION THE JUNGLE UNDERGROWTH IS MADE UP OF JUNGLE LOGS AND JUNGLE LEAVES
Unless you say that Bedrock Edition's "jungle logs and jungle leaves" are unintended.
it MUST be a bug, and it MUST be a bug where the features generated with oak leaves where it should have jungle leaves. Maybe because there wasn't jungle leaves yet, maybe because the biome tricked the terrain generator, just like how we used to have spruce trees with oak leaves on the edge of the two biomes

As you can see we even already have bamboo. And to persuade you in believing it is a actual bug, I have attached a Bedrock Edition shot.

In this shot, the trees close to the undergrowths are oak trees. You can see the two feature different leaves. On the tall jungle tree, you have jungle leaves and you can see that the undergrowth have the same leaves textures.

Issue persistent in 1.17.1
Issue persistent in 1.17.1 using "CavesandCliffsPreview"