"Array size must be 4!" (EXCEPTION) in "src/pocketmine/event/block/SignChangeEvent" at line 86

I found this error on the log.
plugin issue or PMMP issue ?
I can't reproduce

thanks

PMMP #1544 + 30 plugins on my server

Code:

2018-10-12 [17:38:56] [Server thread/CRITICAL]: InvalidArgumentException: "Array size must be 4!" (EXCEPTION) in "src/pocketmine/event/block/SignChangeEvent" at line 86
2018-10-12 [17:38:56] [Server thread/DEBUG]: #0 src/pocketmine/event/block/SignChangeEvent(47): pocketmine\event\block\SignChangeEvent->setLines(array Array())
2018-10-12 [17:38:56] [Server thread/DEBUG]: #1 src/pocketmine/tile/Sign(145): pocketmine\event\block\SignChangeEvent->__construct(pocketmine\block\WallSign object, pocketmine\Player object, array Array())
2018-10-12 [17:38:56] [Server thread/DEBUG]: #2 src/pocketmine/Player(2937): pocketmine\tile\Sign->updateCompoundTag(pocketmine\nbt\tag\CompoundTag object, pocketmine\Player object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #3 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(184): pocketmine\Player->handleBlockEntityData(pocketmine\network\mcpe\protocol\BlockEntityDataPacket object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #4 src/pocketmine/network/mcpe/protocol/BlockEntityDataPacket(54): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleBlockEntityData(pocketmine\network\mcpe\protocol\BlockEntityDataPacket object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #5 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(92): pocketmine\network\mcpe\protocol\BlockEntityDataPacket->handle(pocketmine\network\mcpe\PlayerNetworkSessionAdapter object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #6 src/pocketmine/network/mcpe/protocol/BatchPacket(114): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleDataPacket(pocketmine\network\mcpe\protocol\BlockEntityDataPacket object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #7 src/pocketmine/network/mcpe/PlayerNetworkSessionAdapter(92): pocketmine\network\mcpe\protocol\BatchPacket->handle(pocketmine\network\mcpe\PlayerNetworkSessionAdapter object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #8 src/pocketmine/Player(3056): pocketmine\network\mcpe\PlayerNetworkSessionAdapter->handleDataPacket(pocketmine\network\mcpe\protocol\BatchPacket object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #9 src/pocketmine/network/mcpe/RakLibInterface(161): pocketmine\Player->handleDataPacket(pocketmine\network\mcpe\protocol\BatchPacket object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #10 vendor/pocketmine/raklib/src/server/ServerHandler(98): pocketmine\network\mcpe\RakLibInterface->handleEncapsulated(string 82.XXX.XX.167 45347, raklib\protocol\EncapsulatedPacket object, integer 0)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #11 src/pocketmine/network/mcpe/RakLibInterface(102): raklib\server\ServerHandler->handlePacket()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #12 src/pocketmine/network/Network(94): pocketmine\network\mcpe\RakLibInterface->process()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #13 src/pocketmine/network/mcpe/RakLibInterface(92): pocketmine\network\Network->processInterface(pocketmine\network\mcpe\RakLibInterface object)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #14 vendor/pocketmine/snooze/src/SleeperHandler(120): pocketmine\network\mcpe\RakLibInterface->pocketmine\network\mcpe\{closure}()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #15 vendor/pocketmine/snooze/src/SleeperHandler(82): pocketmine\snooze\SleeperHandler->processNotifications()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #16 src/pocketmine/Server(2259): pocketmine\snooze\SleeperHandler->sleepUntil(double 1539358736.5132)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #17 src/pocketmine/Server(2134): pocketmine\Server->tickProcessor()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #18 src/pocketmine/Server(1700): pocketmine\Server->start()
2018-10-12 [17:38:56] [Server thread/DEBUG]: #19 src/pocketmine/PocketMine(249): pocketmine\Server->__construct(BaseClassLoader object, pocketmine\utils\MainLogger object, string /home/myserver/, string /home/myserver/plugins/)
2018-10-12 [17:38:56] [Server thread/DEBUG]: #20 /home/myserver/PocketMine-MP.phar(1): require(string phar:///home/myserver/PocketMine-MP.phar/src/pocketmine/PocketMine.php)
2018-10-12 [17:38:56] [RakLibServer thread/NOTICE]: Blocked 82.XXX.XX.167 for 5 seconds