Blockentity: Shield

This error took I in mine single player console:

[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield
[17:21:53] [Server thread/WARN]: Unable to resolve BlockEntity for ItemInstance: minecraft:shield