Basically, i'm writing a mod that has to do something when you mount a horse. However, whenever the horse is mounted (or dismounted) it fires twice.

Here's my code: 

@SubscribeEvent
    public void mountEntity(EntityMountEvent event){
        Minecraft.getMinecraft().player.sendMessage(new TextComponentString("horse"));
    }

I'm using 1.12.2 if that makes any difference

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Please update to a modern version of Minecraft to receive support.