diff --git a/src/AcDream.App/Diagnostics/FrameProfiler.cs b/src/AcDream.App/Diagnostics/FrameProfiler.cs
index dd01f9a1..2ac85dcd 100644
--- a/src/AcDream.App/Diagnostics/FrameProfiler.cs
+++ b/src/AcDream.App/Diagnostics/FrameProfiler.cs
@@ -75,7 +75,18 @@ public sealed class FrameProfiler : IDisposable
         bool enabled = RenderingDiagnostics.FrameProfEnabled;
         if (!enabled)
         {
-            if (_wasEnabled) { _gpuTimer?.Stop(); _wasEnabled = false; _lastBoundaryTimestamp = 0; }
+            if (_wasEnabled)
+            {
+                // Dispose (not just Stop) so a later re-enable rebuilds the
+                // query ring fresh — a kept instance would poll slots left
+                // pending from BEFORE the pause and report temporally stale
+                // GPU samples. Safe here: this runs at the top of OnRender
+                // with the GL context current.
+                _gpuTimer?.Dispose();
+                _gpuTimer = null;
+                _wasEnabled = false;
+                _lastBoundaryTimestamp = 0;
+            }
             return;
         }
 
@@ -92,9 +103,14 @@ public sealed class FrameProfiler : IDisposable
         if (!_wasEnabled)
         {
             // First enabled frame (startup or runtime toggle-on): establish
-            // baselines, emit nothing.
+            // baselines, emit nothing. Clear any stage ticks a StageScope
+            // disposed after toggle-off may have accumulated mid-pause —
+            // EndStage still runs on scopes that were live when the flag
+            // flipped, and that partial delta must not leak into the first
+            // re-enabled frame.
             _wasEnabled = true;
             _lastReportTicks = DateTime.UtcNow.Ticks;
+            Array.Clear(_stageAccumTicks);
             _gc0Base = GC.CollectionCount(0); _gc1Base = GC.CollectionCount(1); _gc2Base = GC.CollectionCount(2);
             if (_gpuTimer is null && !_wbDiagActive) _gpuTimer = new GpuFrameTimer(gl);
             if (_wbDiagActive && !_wbDiagNoticePrinted)
diff --git a/src/AcDream.App/Diagnostics/FrameStatsBuffer.cs b/src/AcDream.App/Diagnostics/FrameStatsBuffer.cs
index 080e6ac8..60773235 100644
--- a/src/AcDream.App/Diagnostics/FrameStatsBuffer.cs
+++ b/src/AcDream.App/Diagnostics/FrameStatsBuffer.cs
@@ -56,8 +56,13 @@ public sealed class FrameStatsBuffer
 
     public long Max()
     {
-        long max = 0;
-        for (int i = 0; i < _count; i++)
+        if (_count == 0) return 0;   // documented empty behavior, matches Percentile
+        // Seed from the first live sample so all-negative windows (the alloc
+        // channel can go negative if the boundary ever crosses threads) return
+        // the true max instead of clamping to 0. Slots [0.._count) are always
+        // the live window regardless of ring wraparound.
+        long max = _samples[0];
+        for (int i = 1; i < _count; i++)
             if (_samples[i] > max) max = _samples[i];
         return max;
     }
diff --git a/tests/AcDream.App.Tests/FrameStatsBufferTests.cs b/tests/AcDream.App.Tests/FrameStatsBufferTests.cs
index 0d4cd438..725f370c 100644
--- a/tests/AcDream.App.Tests/FrameStatsBufferTests.cs
+++ b/tests/AcDream.App.Tests/FrameStatsBufferTests.cs
@@ -48,4 +48,12 @@ public class FrameStatsBufferTests
         Assert.Equal(0, buf.Count);
         Assert.Equal(0, buf.Percentile(0.5));
     }
+
+    [Fact]
+    public void Max_AllNegative_ReturnsTrueMax()
+    {
+        var buf = new FrameStatsBuffer(capacity: 4);
+        buf.Push(-5); buf.Push(-2); buf.Push(-9);
+        Assert.Equal(-2, buf.Max());
+    }
 }