Tree turns into dirt in version 1.12.x beta

This tree has a problem with the Minecraft pe version 1.12.x (beta). when I put the tree down, the land became a real dirt slowly, even though it was not touched directly on the ground. Not only put the tree, but the chunk that has just been processed is still grass when the tree is there, the grass becomes dirt slowly. Both of these versions have been tested, namely 1.12.0.4 (Beta), 1.12.0.6 (Beta), 1.12.0.9 (Beta), and 1.12.0.10 (Beta). Previously it had never been like that. Here are some screenshots that I caught on the screen are as follows: