Fix wrong mono streak length handling in corner case

osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs

@@ -45,7 +45,12 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills
             // hits spaced more than a second apart are also exempt from colour strain.
             if (!(current.LastObject is Hit && current.BaseObject is Hit && current.DeltaTime < 1000))
             {
-                previousHitType = null;
+                monoHistory.Clear();
+
+                var currentHit = current.BaseObject as Hit;
+                currentMonoLength = currentHit != null ? 1 : 0;
+                previousHitType = currentHit?.Type;
+
                 return 0.0;
             }
 

osu.Game.Tests/NonVisual/LimitedCapacityQueueTest.cs

@@ -94,5 +94,26 @@ namespace osu.Game.Tests.NonVisual
 
             Assert.Throws<InvalidOperationException>(() => queue.Dequeue());
         }
+
+        [Test]
+        public void TestClearQueue()
+        {
+            queue.Enqueue(3);
+            queue.Enqueue(5);
+            Assert.AreEqual(2, queue.Count);
+
+            queue.Clear();
+            Assert.AreEqual(0, queue.Count);
+            Assert.Throws<ArgumentOutOfRangeException>(() => _ = queue[0]);
+
+            queue.Enqueue(7);
+            Assert.AreEqual(1, queue.Count);
+            Assert.AreEqual(7, queue[0]);
+            Assert.Throws<ArgumentOutOfRangeException>(() => _ = queue[1]);
+
+            queue.Enqueue(9);
+            Assert.AreEqual(2, queue.Count);
+            Assert.AreEqual(9, queue[1]);
+        }
     }
 }

osu.Game/Rulesets/Difficulty/Utils/LimitedCapacityQueue.cs

@@ -40,8 +40,17 @@ namespace osu.Game.Rulesets.Difficulty.Utils
 
             this.capacity = capacity;
             array = new T[capacity];
+            Clear();
+        }
+
+        /// <summary>
+        /// Removes all elements from the <see cref="LimitedCapacityQueue{T}"/>.
+        /// </summary>
+        public void Clear()
+        {
             start = 0;
             end = -1;
+            Count = 0;
         }
 
         /// <summary>