Rain and snow appear/disappear when changing height

As the title states, rain and snow can appear and disappear if the player changes height, generally on the edges of biomes. For instance, in seed 6098993085410235807, if you do /tp 3526.69 149.72 2007.78 334.79 90.00, then fly up and down while it is raining, you can clearly see snow and rain planes appear and disappear. I strongly suspect that this is due to the precipitation rendering code using the player's y-coordinate in place of the motion_blocking heightmap, though upon consulting the game's code using mojang mappings i do not see a clear location where this might be happening, though the code isn't the clearest. here is a video very clearly demonstrating the problem with the above setup: https://youtu.be/WqJTfYPVKyk