Give yourself a sculk sensor with /give and place it in a bottom corner of a chunk section. If you're wondering what a check section is, press f3+g to show chunk outlines: the horizontal and vertical blue lines are the edges of a 16x16x16 chunk section. Place blocks next to the sculk sensor in the adjacent three chunk sections and note that they don't trigger the sculk sensor.

I believe the cause of this issue is that

this.radius = radius;

is missing from the constructor of GenericGameEvent here: https://hub.spigotmc.org/stash/projects/SPIGOT/repos/bukkit/browse/src/main/java/org/bukkit/event/world/GenericGameEvent.java#27. This constructor is used here: https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/browse/nms-patches/net/minecraft/world/level/World.patch#335.