Paper/paper-server/patches/sources/net/minecraft/server/commands/PlaceCommand.java.patch

--- a/net/minecraft/server/commands/PlaceCommand.java
+++ b/net/minecraft/server/commands/PlaceCommand.java
@@ -280,6 +_,7 @@
         if (!structureStart.isValid()) {
             throw ERROR_STRUCTURE_FAILED.create();
         } else {
+            structureStart.generationEventCause = org.bukkit.event.world.AsyncStructureGenerateEvent.Cause.COMMAND; // CraftBukkit - set AsyncStructureGenerateEvent.Cause.COMMAND as generation cause
             BoundingBox boundingBox = structureStart.getBoundingBox();
             ChunkPos chunkPos = new ChunkPos(SectionPos.blockToSectionCoord(boundingBox.minX()), SectionPos.blockToSectionCoord(boundingBox.minZ()));
             ChunkPos chunkPos1 = new ChunkPos(SectionPos.blockToSectionCoord(boundingBox.maxX()), SectionPos.blockToSectionCoord(boundingBox.maxZ()));