diff --git a/osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs b/osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs
index 42e2099e3f..ce6a118d9b 100644
--- a/osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs
+++ b/osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
@@ -40,7 +38,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         private const double time_tail = 4000;
         private const double time_after_tail = 5250;
 
-        private List<JudgementResult> judgementResults;
+        private List<JudgementResult> judgementResults = new List<JudgementResult>();
 
         /// <summary>
         ///     -----[           ]-----
@@ -521,9 +519,9 @@ namespace osu.Game.Rulesets.Mania.Tests
         private void assertLastTickJudgement(HitResult result)
             => AddAssert($"last tick judged as {result}", () => judgementResults.Last(j => j.HitObject is HoldNoteTick).Type, () => Is.EqualTo(result));
 
-        private ScoreAccessibleReplayPlayer currentPlayer;
+        private ScoreAccessibleReplayPlayer currentPlayer = null!;
 
-        private void performTest(List<ReplayFrame> frames, Beatmap<ManiaHitObject> beatmap = null)
+        private void performTest(List<ReplayFrame> frames, Beatmap<ManiaHitObject>? beatmap = null)
         {
             if (beatmap == null)
             {
@@ -569,15 +567,13 @@ namespace osu.Game.Rulesets.Mania.Tests
             AddUntilStep("Beatmap at 0", () => Beatmap.Value.Track.CurrentTime == 0);
             AddUntilStep("Wait until player is loaded", () => currentPlayer.IsCurrentScreen());
 
-            AddUntilStep("Wait for completion", () => currentPlayer.ScoreProcessor?.HasCompleted.Value == true);
+            AddUntilStep("Wait for completion", () => currentPlayer.ScoreProcessor.HasCompleted.Value);
         }
 
         private partial class ScoreAccessibleReplayPlayer : ReplayPlayer
         {
             public new ScoreProcessor ScoreProcessor => base.ScoreProcessor;
 
-            public new GameplayClockContainer GameplayClockContainer => base.GameplayClockContainer;
-
             protected override bool PauseOnFocusLost => false;
 
             public ScoreAccessibleReplayPlayer(Score score)
diff --git a/osu.Game/Beatmaps/Beatmap.cs b/osu.Game/Beatmaps/Beatmap.cs
index 416d655cc3..4f81b26c3e 100644
--- a/osu.Game/Beatmaps/Beatmap.cs
+++ b/osu.Game/Beatmaps/Beatmap.cs
@@ -107,9 +107,12 @@ namespace osu.Game.Beatmaps
                                 // Aggregate durations into a set of (beatLength, duration) tuples for each beat length
                                 .GroupBy(t => Math.Round(t.beatLength * 1000) / 1000)
                                 .Select(g => (beatLength: g.Key, duration: g.Sum(t => t.duration)))
-                                // Get the most common one, or 0 as a suitable default
+                                // Get the most common one, or 0 as a suitable default (see handling below)
                                 .OrderByDescending(i => i.duration).FirstOrDefault();
 
+            if (mostCommon.beatLength == 0)
+                return TimingControlPoint.DEFAULT_BEAT_LENGTH;
+
             return mostCommon.beatLength;
         }
 
diff --git a/osu.Game/Rulesets/UI/Scrolling/Algorithms/IScrollAlgorithm.cs b/osu.Game/Rulesets/UI/Scrolling/Algorithms/IScrollAlgorithm.cs
index f78509f919..437e5a5e38 100644
--- a/osu.Game/Rulesets/UI/Scrolling/Algorithms/IScrollAlgorithm.cs
+++ b/osu.Game/Rulesets/UI/Scrolling/Algorithms/IScrollAlgorithm.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
 {
     public interface IScrollAlgorithm