Title. Trying to place a 3x3 Yurt results in the Yurt being placed (on the server, but on the client the blocks are invisible) but the item stays enchanted and still contains said 3x3 blocks with contents.

Fixed it by filling the 3x3 area with blocks until the glitched banner block appeared.

at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232) ~[?:?]
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:646) ~[?:?]
at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:696) ~[?:?]
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) ~[?:?]
at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:711) ~[?:?]
at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:717) ~[?:?]
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?]
at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:159) ~[?:?]
at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:734) ~[?:?]
at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) ~[?:?]
at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?]
at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18) ~[?:?]
at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[?:?]
at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:10) ~[?:?]
at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:36) ~[?:?]
at net.minecraft.network.play.ServerPlayNetHandler.func_184337_a(ServerPlayNetHandler.java:958) ~[?:?]
at net.minecraft.server.management.PlayerInteractionManager.func_219441_a(PlayerInteractionManager.java:353) ~[?:?]
at net.minecraft.item.ItemStack.func_196084_a(ItemStack.java:186) ~[?:?]
at net.minecraftforge.common.ForgeHooks.onPlaceItemIntoWorld(ForgeHooks.java:651) ~[forge:?]
at commoble.bagofyurting.BagOfYurtingItem.func_195939_a(BagOfYurtingItem.java:181) ~[bagofyurting:1.2.0.1]
at commoble.bagofyurting.BagOfYurtingItem.unloadBag(BagOfYurtingItem.java:213) ~[bagofyurting:1.2.0.1]
at commoble.bagofyurting.BagOfYurtingData.attemptUnloadIntoWorld(BagOfYurtingData.java:176) ~[bagofyurting:1.2.0.1]
at java.util.ArrayList.forEach(ArrayList.java:1541) ~[?:?]
at commoble.bagofyurting.BagOfYurtingData.lambda$attemptUnloadIntoWorld$7(BagOfYurtingData.java:176) ~[bagofyurting:1.2.0.1]
at commoble.bagofyurting.BagOfYurtingData$StateData.setBlockEntityData(BagOfYurtingData.java:440) ~[bagofyurting:1.2.0.1]
at commoble.bagofyurting.api.BagOfYurtingAPI.lambda$static$1(BagOfYurtingAPI.java:15) ~[bagofyurting:1.2.0.1]
at net.minecraft.tileentity.BannerTileEntity.func_230337_a_(BannerTileEntity.java:96) ~[?:?]
java.lang.ClassCastException: class net.minecraft.block.AirBlock cannot be cast to class net.minecraft.block.AbstractBannerBlock (net.minecraft.block.AirBlock and net.minecraft.block.AbstractBannerBlock are in unnamed module of loader cpw.mods.modlauncher.TransformingClassLoader @5d2a86c0)
Error executing task on Server