What I expected to happen was...:
Didn't expect this.
What actually happened was...:
Breaking blocks under leaves (of any kind), pretty much under trees, makes the snow/rain particles pop on your whole screen for a second I dug up some dirt/gravel/stone aswell and sometimes they do that aswell, not only when breaking wood and leaves, I haven't exactly fully tested this.
(Note: This is not because of my texture pack, I just don't have screenshots with the default one)
Steps to Reproduce:
1. Break leaves/wood/any other block under a tree/under leaves
Environment
Windows 10, latest version of java as of 30th of April 2020
This was fixed in 20w18a, however worlds opened in 20w17a will remain affected by this issue. You need to optimize the world and erase its cache. For instructions on how to do that, please look at the instructions from MC-179845.