Affects Version/s: Minecraft 19w07a, Minecraft 19w08a
Fix Version/s: None
Environment:Windows 10, lots o' RAM, other specs are in screenshots.
Symptom - Growing bamboo within a chunk causes lag within a radius of the chunk where the bamboo is located. If inside the radius then there's a very noticeable lag spike every time bamboo is growing. If outside the radius then there's no lag spike at all while the bamboo is growing.
How to duplicate - Create a flat peaceful world. Plant bamboo on every block within a single chunk. Wait for the bamboo to grow and you'll notice lag spikes as the bamboo gets taller. Crouch-walk away from the growing bamboo and find the block under you where the lag completely stops, and place a block on the ground. Continue testing the area around the bamboo until you've drawn a border where the lag is noticeable, and you'll draw a circle.
= x/z radius where lag is evident.
= if player is outside of the circle, there's no bamboo lag.
= if player is inside the circle, there's lag spikes when bamboo is growing.
= if a block is updated outside of the chunk border where the bamboo is located then there will be no lag.
= if a block is updated on or inside of the chunk border where the bamboo is located then there will be a lag spike.
Other observations - The circular range also follows the 'y' axis, so the lag range is spherical rather than circular. I haven't yet tested this lag issue with other plants besides bamboo.