The bug
The Json exception that is thrown when a score component has no name or objective key is misspelled. It should say "at least", not "a least".
A score component needs a least a name and an objective
How to reproduce
/tellraw @s {"score":{}}
Affected class and method
Minecraft 1.8 decompiled using MCP
Class: net.minecraft.util.IChatComponent.Serializer
Method: public IChatComponent deserialize(JsonElement p_deserialize_1_, Type p_deserialize_2_, JsonDeserializationContext p_deserialize_3_)
Minecraft 16w07a
Class: eu.a
Method: public eu a(JsonElement ?, Type ?, JsonDeserializationContext ?) throws JsonParseException