MCPE-187335 partly fixed some of the disparity between Java and Bedrock when it came to growing pale oak trees, but there still exists a major difference between both editions, which is: pale oak trees grown by the player can generate a pale moss patch at their base on Java, meanwhile, this feature is absent on Bedrock.

Alongside the pale moss patch generated at the trees' bases on Java, you'll also observe how they generate other vegetation, such as pale moss carpets and grass.

From the 1.21.50.24 changelog:

Pale Oak Saplings now grow into Pale Oaks with Hanging Pale Moss on them, but no Pale Moss patch at their base

Steps to reproduce:

1. Plant pale oak saplings in a 2x2 formation.
2. Bonemeal one of them until a tree is grown.
3. Repeat these steps 1 and 2 on both Java and Bedrock a few times.

Observed results:
The trees grown on Bedrock will never generate a pale moss patch at their base, meanwhile on Java, they sometimes will.

Expected results:
The feature of generating a pale moss patch at the base of the tree should be present on both editions.