[23:39:15] [MV-Inv Profile Write Thread/WARN]: [Multiverse-Inventories] Error while building configuration map.
java.lang.NullPointerException: null value in entry: skull-owner=null
	at com.google.common.collect.CollectPreconditions.checkEntryNotNull(CollectPreconditions.java:33) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
	at com.google.common.collect.ImmutableMap.entryOf(ImmutableMap.java:135) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
	at com.google.common.collect.ImmutableMap$Builder.put(ImmutableMap.java:206) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
	at org.bukkit.craftbukkit.v1_8_R2.inventory.CraftMetaSkull.serialize(CraftMetaSkull.java:150) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
	at org.bukkit.craftbukkit.v1_8_R2.inventory.CraftMetaItem.serialize(CraftMetaItem.java:851) ~[spigot-1.8.3.jar:git-Spigot-870264a-0a645a2]
	at com.onarandombox.multiverseinventories.util.JsonConfiguration.buildMap(JsonConfiguration.java:55) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.JsonConfiguration.buildMap(JsonConfiguration.java:56) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.JsonConfiguration.buildMap(JsonConfiguration.java:46) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.JsonConfiguration.buildMap(JsonConfiguration.java:46) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.JsonConfiguration.saveToString(JsonConfiguration.java:32) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.EncodedJsonConfiguration.save(EncodedJsonConfiguration.java:30) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData.processProfileWrite(FlatFilePlayerData.java:243) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData.access$000(FlatFilePlayerData.java:30) [Multiverse-Inventories-2.5.jar:?]
	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData$FileWriteThread.run(FlatFilePlayerData.java:209) [Multiverse-Inventories-2.5.jar:?]