The plugin kicks me out when I try to open crate(entity)

09.04 22:29:26 [Server] Server thread/CRITICAL InvalidStateException: "Entity is not registered" (EXCEPTION) in "src/pocketmine/entity/Entity" at line 864
09.04 22:29:26 [Server] Server thread/DEBUG #0 plugins/Festival.phar/src/genboy/Festival/Festival(2393): pocketmine\entity\Entity->getSaveId()
09.04 22:29:26 [Server] Server thread/DEBUG #1 plugins/Festival.phar/src/genboy/Festival/Festival(1884): genboy\Festival\Festival->canEntitySpawn(object mysterybox\entity\MysterySkull)
09.04 22:29:26 [Server] Server thread/DEBUG #2 src/pocketmine/plugin/MethodEventExecutor(42): genboy\Festival\Festival->onEntitySpawn(object pocketmine\event\entity\EntitySpawnEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #3 src/pocketmine/plugin/RegisteredListener(80): pocketmine\plugin\MethodEventExecutor->execute(object genboy\Festival\Festival, object pocketmine\event\entity\EntitySpawnEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #4 src/pocketmine/event/Event(88): pocketmine\plugin\RegisteredListener->callEvent(object pocketmine\event\entity\EntitySpawnEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #5 src/pocketmine/entity/Entity(637): pocketmine\event\Event->call()
09.04 22:29:26 [Server] Server thread/DEBUG #6 plugins/MysteryBox-master/src/mysterybox/entity/MysterySkull(86): pocketmine\entity\Entity->__construct(object pocketmine\level\Level, object pocketmine\nbt\tag\CompoundTag)
09.04 22:29:26 [Server] Server thread/DEBUG #7 plugins/MysteryBox-master/src/mysterybox/MysteryBox(177): mysterybox\entity\MysterySkull->__construct(object pocketmine\Player, object mysterybox\tile\MysteryTile, object mysterybox\MysteryBox)
09.04 22:29:26 [Server] Server thread/DEBUG #8 plugins/MysteryBox-master/src/mysterybox/EventListener(119): mysterybox\MysteryBox->open(object pocketmine\Player, object mysterybox\tile\MysteryTile)
09.04 22:29:26 [Server] Server thread/DEBUG #9 src/pocketmine/plugin/MethodEventExecutor(42): mysterybox\EventListener->onInteract(object pocketmine\event\player\PlayerInteractEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #10 src/pocketmine/plugin/RegisteredListener(80): pocketmine\plugin\MethodEventExecutor->execute(object mysterybox\EventListener, object pocketmine\event\player\PlayerInteractEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #11 src/pocketmine/event/Event(88): pocketmine\plugin\RegisteredListener->callEvent(object pocketmine\event\player\PlayerInteractEvent)
09.04 22:29:26 [Server] Server thread/DEBUG #12 src/pocketmine/level/Level(1862): pocketmine\event\Event->call()
09.04 22:29:26 [Server] Server thread/DEBUG #13 src/pocketmine/Player(2383): pocketmine\level\Level->useItemOn(object pocketmine\math\Vector3, object pocketmine\item\ItemBlock, integer 2, object pocketmine\math\Vector3, object pocketmine\Player, boolean 1)
09.04 22:29:26 [Server] Server thread/DEBUG #14 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(150): pocketmine\Player->handleInventoryTransaction(object pocketmine\network\mcpe\protocol\InventoryTransactionPacket)
09.04 22:29:26 [Server] Server thread/DEBUG #15 src/pocketmine/network/mcpe/protocol/InventoryTransactionPacket(178): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleInventoryTransaction(object pocketmine\network\mcpe\protocol\InventoryTransactionPacket)
09.04 22:29:26 [Server] Server thread/DEBUG #16 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(110): pocketmine\network\mcpe\protocol\InventoryTransactionPacket->handle(object pocketmine\network\mcpe\PlayerNetworkSessionAdapter)
09.04 22:29:26 [Server] Server thread/DEBUG #17 src/pocketmine/network/mcpe/protocol/BatchPacket(127): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleDataPacket(object pocketmine\network\mcpe\protocol\InventoryTransactionPacket)
09.04 22:29:26 [Server] Server thread/DEBUG #18 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(110): pocketmine\network\mcpe\protocol\BatchPacket->handle(object pocketmine\network\mcpe\PlayerNetworkSessionAdapter)
09.04 22:29:26 [Server] Server thread/DEBUG #19 src/pocketmine/Player(3096): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleDataPacket(object pocketmine\network\mcpe\protocol\BatchPacket)
09.04 22:29:26 [Server] Server thread/DEBUG #20 src/pocketmine/network/mcpe/RakLibInterface(169): pocketmine\Player->handleDataPacket(object pocketmine\network\mcpe\protocol\BatchPacket)
09.04 22:29:26 [Server] Server thread/DEBUG #21 vendor/pocketmine/raklib/src/server/ServerHandler(99): pocketmine\network\mcpe\RakLibInterface->handleEncapsulated(string[18] 68.7.150.203 61679, object raklib\protocol\EncapsulatedPacket, integer 0)
09.04 22:29:26 [Server] Server thread/DEBUG #22 src/pocketmine/network/mcpe/RakLibInterface(109): raklib\server\ServerHandler->handlePacket()
09.04 22:29:26 [Server] Server thread/DEBUG #23 src/pocketmine/network/mcpe/RakLibInterface(99): pocketmine\network\mcpe\RakLibInterface->process()
09.04 22:29:26 [Server] Server thread/DEBUG #24 vendor/pocketmine/snooze/src/SleeperHandler(123): pocketmine\network\mcpe\RakLibInterface->pocketmine\network\mcpe{closure}()
09.04 22:29:26 [Server] Server thread/DEBUG #25 vendor/pocketmine/snooze/src/SleeperHandler(85): pocketmine\snooze\SleeperHandler->processNotifications()
09.04 22:29:26 [Server] Server thread/DEBUG #26 src/pocketmine/Server(2146): pocketmine\snooze\SleeperHandler->sleepUntil(double 1586471366.7237)
09.04 22:29:26 [Server] Server thread/DEBUG #27 src/pocketmine/Server(1990): pocketmine\Server->tickProcessor()
09.04 22:29:26 [Server] Server thread/DEBUG #28 src/pocketmine/Server(1584): pocketmine\Server->start()
09.04 22:29:26 [Server] Server thread/DEBUG #29 src/pocketmine/PocketMine(273): pocketmine\Server->__construct(object BaseClassLoader, object pocketmine\utils\MainLogger, string[47] /, string[55] /plugins/)
09.04 22:29:26 [Server] Server thread/DEBUG #30 src/pocketmine/PocketMine(296): pocketmine\server()
09.04 22:29:26 [Server] Server thread/DEBUG #31 (11): require(string[107] phar:///PMMP-Latest-Stable.phar/sr)