inventory holder is not set for certain inventory types

package com.example;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.bukkit.Material;
import org.bukkit.Server;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.command.TabExecutor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.inventory.InventoryType;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.InventoryHolder;
import org.bukkit.inventory.ItemStack;

public class TestCommandExecutor implements TabExecutor, Listener {
	
	private final ExamplePlugin plugin;
	
	public TestCommandExecutor(ExamplePlugin plugin) {
		this.plugin = plugin;
		plugin.getCommand("test").setExecutor(this);
		plugin.getServer().getPluginManager().registerEvents(this, plugin);
	}

	@Override
	public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
		if (sender instanceof Player) {
			Player player = (Player) sender;
			
			if (args.length == 0) {
				Inventory testInventory = new TestInventoryHolder(player.getServer()).getInventory();
				testInventory.addItem(new ItemStack(Material.COBBLESTONE), new ItemStack(Material.DIAMOND), new ItemStack(Material.OAK_LOG));
				player.openInventory(testInventory);
			} else {
				String firstArg = args[0];
				Inventory testInventory = new TestInventoryHolder(player.getServer(), InventoryType.valueOf(firstArg.toUpperCase())).getInventory();
				testInventory.addItem(new ItemStack(Material.COBBLESTONE), new ItemStack(Material.DIAMOND), new ItemStack(Material.OAK_LOG));
				player.openInventory(testInventory);
			}
			
			return true;
		}
		
		return false;
	}
	
	@Override
	public List<String> onTabComplete(CommandSender sender, Command command, String alias, String[] args) {
		return Stream.of(InventoryType.values()).map(InventoryType::name).collect(Collectors.toList());
	}
	
	@EventHandler
	public void onInventoryClick(InventoryClickEvent event) {
		Inventory topInventory = event.getView().getTopInventory();
		if (topInventory.getHolder() instanceof TestInventoryHolder) {
			/* Correct behaviour - branch is correctly taken for the following inventory types:
			 * ANVIL
			 * CHEST
			 * ENCHANTING
			 * ENDER_CHEST
			 * PLAYER
			 * SHULKER_BOX
			 * WORKBENCH
			 */
			plugin.getLogger().info("DEBUG clicked TestInventoryHolder - plugin is " + (plugin.isEnabled() ? "enabled" : "disabled") + ". cancelling event.");
			event.setCancelled(true);
		} else {
			/* Spigot bug - this branch is taken for the following inventory types because the inventory holder is null:
			 * BEACON
			 * BREWING
			 * DISPENSER
			 * DROPPER
			 * FURNACE
			 * HOPPER
			 */
			plugin.getLogger().info("DEBUG clicked an inventory not held by TestInventoryHolder");
			plugin.getLogger().info("DEBUG topinventory holder = " + topInventory.getHolder());
		}
	}
	
	private static class TestInventoryHolder implements InventoryHolder {
		
		private final Inventory inventory;
		
		public TestInventoryHolder(Server server) {
			this.inventory = server.createInventory(this, 3 * 9, "Test Inventory");
		}
		
		public TestInventoryHolder(Server server, InventoryType type) {
			this.inventory = server.createInventory(this, type);
		}
		
		public Inventory getInventory() {
			return inventory;
		}
		
	}

}