[1.7.2]Spurious PlayerUseItemEvent on specific servers only? SOLVED

I'm trying to add a bow charge indicator to the game overlay - a green transparent rectangle showing up at full charge.

I'm registerig a Event listener to get the Bow use:

public void load(FMLInitializationEvent event){
public static final BowListener bowListener = new BowListener();
...	
MinecraftForge.EVENT_BUS.register(bowListener);

and I track the bow charge

public class BowListener {

public boolean scopeOn = false;
public float charge;

@SubscribeEvent
public void startUsingBow (PlayerUseItemEvent.Start event){
	if (itemNotBow(event.item.getItem(), true)) return;
	openScope();
	charge = calcCharge(event.item.getItem(), event.duration);
}

@SubscribeEvent
public void continueUsingBow (PlayerUseItemEvent.Tick event){
	if (itemNotBow(event.item.getItem(), false)) return;
	charge = calcCharge(event.item.getItem(), event.duration);
}

@SubscribeEvent
public void stopUsingBow (PlayerUseItemEvent.Stop event){
	if (itemNotBow(event.item.getItem(), false))return;
	cancelScope();
}

private boolean itemNotBow (Item item, boolean start){
	if (item instanceof ItemBow) {
		if (start && scopeOn) {
			FMLLog.info("DDDDDD>>> startUsingBow but scope still active");
		}
		if (!start && !scopeOn) {
			FMLLog.info("DDDDDD>>> UsingBow but scope not active");
		}
		return false;
	}
	if (scopeOn) {
		FMLLog.info("DDDDDD>>> UsingOtherThanBow but scope still active");
	}
	cancelScope();
	return true;
}

private void cancelScope () {
	charge = 0.0F;
	scopeOn = false;
}

private void openScope () {
	scopeOn = true;
}

private float calcCharge (Item item, int duration) {

	int j = item.getMaxItemUseDuration(null) - duration;
        float f = (float)j / 20.0F;

        f = (f * f + f * 2.0F) / 3.0F;

        if ((double)f < 0.1D) return 0.0F;
        if (f > 1.0F) return 1.0F;

        return f;
}
}

This works great for most of the servers, BUT if i'm going to certain other servers like shotbow.net, I'm getting called for "impossible" PlayerUseItemEvents.

I have set a BP on the line which holds "FMLLog.info("DDDDDD>>> UsingOtherThanBow but scope still active");" and get following stackdump:

Thread [Client thread] (Suspended (breakpoint at line 45 in BowListener))	
BowListener.itemNotBow(Item, boolean) line: 45	
BowListener.continueUsingBow(PlayerUseItemEvent$Tick) line: 24	
ASMEventHandler_4_BowListener_continueUsingBow_Tick.invoke(Event) line: not available	
ASMEventHandler.invoke(Event) line: 51	
EventBus.post(Event) line: 122	
ForgeEventFactory.onItemUseTick(EntityPlayer, ItemStack, int) line: 149	
EntityOtherPlayerMP(EntityPlayer).onUpdate() line: 281	
EntityOtherPlayerMP.onUpdate() line: 72	
WorldClient(World).updateEntityWithOptionalForce(Entity, boolean) line: 2254	
WorldClient(World).updateEntity(Entity) line: 2214	
WorldClient(World).updateEntities() line: 2064	
Minecraft.runTick() line: 2065	
Minecraft.runGameLoop() line: 997	
Minecraft.run() line: 912	
Main.main(String[]) line: 112	
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
NativeMethodAccessorImpl.invoke(Object, Object[]) line: not available	
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: not available	
Method.invoke(Object, Object...) line: not available	
Launch.launch(String[]) line: 134	
Launch.main(String[]) line: 28	

and item is an ItemFood:"melon"  But I don't have any melons, not in inventory nor in hotbar. 

Did someone already observe this?

I'm a noob - I forgot to check the player in the event.  I changed to:

public class BowListener {

public boolean scopeOn = false;
public float charge;

@SubscribeEvent
public void startUsingBow (PlayerUseItemEvent.Start event){

	if (itemNotBow(event)) return;
	scopeOn = true;
	charge = calcCharge(event.item.getItem(), event.duration);
}

@SubscribeEvent
public void continueUsingBow (PlayerUseItemEvent.Tick event){

	if (itemNotBow(event)) return;
	charge = calcCharge(event.item.getItem(), event.duration);
}

@SubscribeEvent
public void stopUsingBow (PlayerUseItemEvent.Stop event){

	if (itemNotBow(event)) return;
	charge = 0.0F;
	scopeOn = false;
}

private boolean itemNotBow (PlayerUseItemEvent event){

	if (event.entityPlayer.getEntityId() != Minecraft.getMinecraft().thePlayer.getEntityId()) return true; // someone other is using item ...
	if (event.item.getItem() instanceof ItemBow) return false;
	return true;
}

private float calcCharge (Item item, int duration) {

	int j = item.getMaxItemUseDuration(null) - duration;
        float f = (float)j / 20.0F;

        f = (f * f + f * 2.0F) / 3.0F;

        if ((double)f < 0.1D) return 0.0F;
        if (f > 1.0F) return 1.0F;

        return f;
}
}