Large oak trees fail to spawning or spawning abnormally in forest & forest hills in version 1.9.0,1.9.1,1.9.2,1.9.3&1.9.4.

seed:527160204975065564,version 1.9.4
When i create the world, there are some large oak trees generate normally,like picture-1. The tree at 484 284 is one of them.
But when i delete this world,close the game, restart the game, regenerate the world, there are not any large oak trees at all. The the trees,which are intended to be large oak trees,become one kind of "strange" small oak trees,they are different from normal small oak trees,they seem to have more leaves.Just like in the picture-2 below,The tree at 484 284 became small "strange" oak tree.just like in MC-10534.
When i restart the game,recreate the world again,all of the "strange" kind of trees become extremely large.they seem to be a lot bigger than normal large oak trees.Like in picture-3,the tree at 484 284 became extremely large.
When i repeat this step to restart the game and recreate the world for a lot of times,the 3 cases above seem to happen randomly.
It seems it's a bug: Sometimes large oak trees fail to generate,sometimes large oak trees become larger than designed.