diff --git a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/BlockBreakListener.java b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/BlockBreakListener.java
index 752d26cc..451f8b6b 100644
--- a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/BlockBreakListener.java
+++ b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/BlockBreakListener.java
@@ -18,6 +18,7 @@ import org.bukkit.inventory.ItemStack;
 import fr.neatmonster.nocheatplus.checks.CheckListener;
 import fr.neatmonster.nocheatplus.checks.CheckType;
 import fr.neatmonster.nocheatplus.checks.inventory.Items;
+import fr.neatmonster.nocheatplus.compat.AlmostBoolean;
 import fr.neatmonster.nocheatplus.hooks.NCPExemptionManager;
 import fr.neatmonster.nocheatplus.permissions.Permissions;
 import fr.neatmonster.nocheatplus.utilities.BlockProperties;
@@ -48,7 +49,7 @@ public class BlockBreakListener extends CheckListener {
     /** The wrong block check. */
     private final WrongBlock wrongBlock = addCheck(new WrongBlock());
     
-    private boolean isInstaBreak = false;
+    private AlmostBoolean isInstaBreak = AlmostBoolean.NO;
     
     public BlockBreakListener(){
     	super(CheckType.BLOCKBREAK);
@@ -73,7 +74,7 @@ public class BlockBreakListener extends CheckListener {
         
     	// Cancelled events only leads to resetting insta break.
     	if (event.isCancelled()) {
-    		isInstaBreak = false;
+    		isInstaBreak = AlmostBoolean.NO;
     		return;
     	}
     	
@@ -142,7 +143,7 @@ public class BlockBreakListener extends CheckListener {
 //        	data.clickedX = Integer.MAX_VALUE;
         }
         
-        if (isInstaBreak) {
+        if (isInstaBreak.decideOptimistically()) {
         	data.wasInstaBreak = now;
         }
         else {
@@ -152,7 +153,7 @@ public class BlockBreakListener extends CheckListener {
         // Adjust data.
         data.fastBreakBreakTime = now;
 //        data.fastBreakfirstDamage = now;
-        isInstaBreak = false;
+        isInstaBreak = AlmostBoolean.NO;
     }
 
     /**
@@ -185,18 +186,32 @@ public class BlockBreakListener extends CheckListener {
     	
     	// Return if it is not left clicking a block. 
     	// (Allows right click to be ignored.)
-    	isInstaBreak = false;
-        if (event.getAction() != Action.LEFT_CLICK_BLOCK) return;
+    	isInstaBreak = AlmostBoolean.NO;
+        if (event.getAction() != Action.LEFT_CLICK_BLOCK) {
+        	return;
+        }
         checkBlockDamage(event.getPlayer(), event.getClickedBlock(), event);
-        
     }
     
-    @EventHandler(
-    		ignoreCancelled = false, priority = EventPriority.MONITOR)
+    @EventHandler(ignoreCancelled = false, priority = EventPriority.LOWEST)
+    public void onBlockDamageLowest(final BlockDamageEvent event) {
+    	if (event.getInstaBreak()) {
+    		// Indicate that this might have been set by CB/MC.
+    		isInstaBreak = AlmostBoolean.MAYBE;
+    	}
+    }
+    
+    @EventHandler(ignoreCancelled = false, priority = EventPriority.MONITOR)
     public void onBlockDamage(final BlockDamageEvent event) {
-//    	System.out.println("Damage("+event.isCancelled()+"): " + event.getBlock());
-    	if (!event.isCancelled() && event.getInstaBreak()) isInstaBreak = true;
-    	else isInstaBreak = false;
+    	if (!event.isCancelled() && event.getInstaBreak()) {
+    		// Keep MAYBE.
+    		if (isInstaBreak != AlmostBoolean.MAYBE) {
+    			isInstaBreak = AlmostBoolean.YES;
+    		}
+    	}
+    	else {
+    		isInstaBreak = AlmostBoolean.NO;
+    	}
     	checkBlockDamage(event.getPlayer(), event.getBlock(), event);
     }
     
diff --git a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/FastBreak.java b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/FastBreak.java
index b98b6d60..364feef7 100644
--- a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/FastBreak.java
+++ b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/FastBreak.java
@@ -10,6 +10,7 @@ import fr.neatmonster.nocheatplus.actions.ParameterName;
 import fr.neatmonster.nocheatplus.checks.Check;
 import fr.neatmonster.nocheatplus.checks.CheckType;
 import fr.neatmonster.nocheatplus.checks.ViolationData;
+import fr.neatmonster.nocheatplus.compat.AlmostBoolean;
 import fr.neatmonster.nocheatplus.permissions.Permissions;
 import fr.neatmonster.nocheatplus.utilities.BlockProperties;
 import fr.neatmonster.nocheatplus.utilities.PotionUtil;
@@ -40,7 +41,7 @@ public class FastBreak extends Check {
      * @param elaspedTime
      * @return true, if successful
      */
-    public boolean check(final Player player, final Block block, final boolean isInstaBreak, final BlockBreakConfig cc, final BlockBreakData data) {
+    public boolean check(final Player player, final Block block, final AlmostBoolean isInstaBreak, final BlockBreakConfig cc, final BlockBreakData data) {
     	final long now = System.currentTimeMillis();
         boolean cancel = false;
         
@@ -65,11 +66,12 @@ public class FastBreak extends Check {
         }
           
         // Check if the time used time is lower than expected.
-//        if (isInstaBreak){
-//        	// Ignore those for now.
-//        }
-//        else 
-        if (elapsedTime < 0){
+        if (isInstaBreak.decideOptimistically()){
+        	// Ignore those for now.
+        	// TODO: Find out why this was commented out long ago a) did not fix mcMMO b) exploits.
+        	// TODO: Maybe adjust time to min(time, SOMETHING) for MAYBE/YES.
+        }
+        else if (elapsedTime < 0){
         	// Ignore it. TODO: ?
         }
         else if (elapsedTime + cc.fastBreakDelay < breakingTime){
@@ -114,7 +116,7 @@ public class FastBreak extends Check {
         	final ItemStack stack = player.getItemInHand();
         	final boolean isValidTool = BlockProperties.isValidTool(blockId, stack);
         	final double haste = PotionUtil.getPotionEffectAmplifier(player, PotionEffectType.FAST_DIGGING);
-        	String msg = (isInstaBreak ? "[Insta]" : "[Normal]") + "[" + blockId + "] "+ elapsedTime + "u / " + breakingTime +"r (" + (isValidTool?"tool":"no-tool") + ")" + (haste == Double.NEGATIVE_INFINITY ? "" : " haste=" + ((int) haste + 1));
+        	String msg = (isInstaBreak.decideOptimistically() ? ("[Insta=" + isInstaBreak + "]") : "[Normal]") + "[" + blockId + "] "+ elapsedTime + "u / " + breakingTime +"r (" + (isValidTool?"tool":"no-tool") + ")" + (haste == Double.NEGATIVE_INFINITY ? "" : " haste=" + ((int) haste + 1));
         	player.sendMessage(msg);
 //        	net.minecraft.server.Item mcItem = net.minecraft.server.Item.byId[stack.getTypeId()];
 //        	if (mcItem != null){
diff --git a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/WrongBlock.java b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/WrongBlock.java
index 3a415af5..4341395d 100644
--- a/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/WrongBlock.java
+++ b/NCPCore/src/main/java/fr/neatmonster/nocheatplus/checks/blockbreak/WrongBlock.java
@@ -6,6 +6,7 @@ import org.bukkit.entity.Player;
 import fr.neatmonster.nocheatplus.checks.Check;
 import fr.neatmonster.nocheatplus.checks.CheckType;
 import fr.neatmonster.nocheatplus.checks.combined.Improbable;
+import fr.neatmonster.nocheatplus.compat.AlmostBoolean;
 import fr.neatmonster.nocheatplus.permissions.Permissions;
 import fr.neatmonster.nocheatplus.utilities.TrigUtil;
 
@@ -26,7 +27,7 @@ public class WrongBlock extends Check {
 	 * @param isInstaBreak 
 	 * @return
 	 */
-	public boolean check(final Player player, final Block block, final BlockBreakConfig cc, final BlockBreakData data, final boolean isInstaBreak) {
+	public boolean check(final Player player, final Block block, final BlockBreakConfig cc, final BlockBreakData data, final AlmostBoolean isInstaBreak) {
         
         boolean cancel = false;
         
@@ -34,6 +35,7 @@ public class WrongBlock extends Check {
         final int dist = Math.min(4, data.clickedX == Integer.MAX_VALUE ? 100 : TrigUtil.manhattan(data.clickedX, data.clickedY, data.clickedZ, block));
         final boolean wrongBlock;
         final long now = System.currentTimeMillis();
+        // TODO: Remove isInstaBreak argument or use it.
         if (dist == 0) {
         	if (wrongTime) {
         		data.fastBreakBreakTime = now;