Steps to Reproduce:

• Open up Preview world
• Find a snowy biome (e.g: ice_plains)
• Plant Spruce sapling and bonemeal
• Dig a hole surrounding the tree and fill it with water source blocks
• Place snow layers all over the leaves on the tree
• observe that the falling leaves disappear as soon as they touch the bottom of the water, but the snow particles gently fades away as they touch the bottom of the water.

Expected result:

The leaves also fade away gently when they touch the bottom of the water.

video will be added soon