diff --git a/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/StaleInstanceProbe.cs b/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/StaleInstanceProbe.cs
index 799e113a..c07ff89c 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/StaleInstanceProbe.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DeploymentManager/StaleInstanceProbe.cs
@@ -1,21 +1,19 @@
-using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Transport;
 
 namespace ZB.MOM.WW.ScadaBridge.DeploymentManager;
 
 /// <summary>Recomputes deployment revisions from authoritative configuration on every probe.
-/// Process-local watermarks cannot prove freshness after another central changes the shared store.</summary>
+/// Process-local watermarks cannot prove freshness after another central changes the shared store,
+/// so nothing is memoised across calls.</summary>
 public sealed class StaleInstanceProbe : IStaleInstanceProbe
 {
     private readonly IFlatteningPipeline _flatteningPipeline;
 
-    /// <summary>Initializes the authoritative probe. Watermark remains a constructor compatibility dependency.</summary>
+    /// <summary>Initializes the authoritative probe.</summary>
     /// <param name="flatteningPipeline">The pipeline used to flatten instances for staleness comparison.</param>
-    /// <param name="watermark">The template graph watermark; retained only for constructor compatibility.</param>
-    public StaleInstanceProbe(IFlatteningPipeline flatteningPipeline, ITemplateGraphWatermark watermark)
+    public StaleInstanceProbe(IFlatteningPipeline flatteningPipeline)
     {
         _flatteningPipeline = flatteningPipeline ?? throw new ArgumentNullException(nameof(flatteningPipeline));
-        ArgumentNullException.ThrowIfNull(watermark);
     }
 
     /// <inheritdoc />
@@ -26,7 +24,4 @@ public sealed class StaleInstanceProbe : IStaleInstanceProbe
             validateScripts: false, session).ConfigureAwait(false);
         return result.IsSuccess ? result.Value.RevisionHash : null;
     }
-
-    /// <summary>Compatibility hook: probes no longer retain process-global results.</summary>
-    public static void ClearMemos() { }
 }
diff --git a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
index 617f46df..2839e223 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/DeploymentServiceTests.cs
@@ -717,16 +717,12 @@ public class DeploymentServiceTests : TestKit
     public async Task StaleInstanceProbe_RequestsValidateScriptsFalse()
     {
         // The Transport stale-instance probe also only needs the hash — same skip.
-        // The probe memoises per-instance against the graph watermark, so start
-        // from a clean memo or a sibling test's entry would satisfy the probe
-        // without a flatten at all.
-        StaleInstanceProbe.ClearMemos();
 
         _pipeline.CreateSession().Returns(_ => new FlattenSession(new TemplateGraphWatermark()));
         _pipeline.FlattenAndValidateAsync(5, Arg.Any<CancellationToken>(), Arg.Any<bool>(), Arg.Any<FlattenSession?>())
             .Returns(Result<FlatteningPipelineResult>.Success(
                 new FlatteningPipelineResult(new FlattenedConfiguration(), "sha256:probe", ValidationResult.Success())));
-        var probe = new StaleInstanceProbe(_pipeline, new TemplateGraphWatermark());
+        var probe = new StaleInstanceProbe(_pipeline);
 
         var hash = await probe.GetCurrentRevisionHashAsync(5);
 
diff --git a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/StaleInstanceProbeTests.cs b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/StaleInstanceProbeTests.cs
index cd93eb51..0bb3b947 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/StaleInstanceProbeTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests/StaleInstanceProbeTests.cs
@@ -8,20 +8,11 @@ using ZB.MOM.WW.ScadaBridge.TemplateEngine.Flattening;
 namespace ZB.MOM.WW.ScadaBridge.DeploymentManager.Tests;
 
 /// <summary>
-/// The staleness fast path: <see cref="StaleInstanceProbe"/> memoises a computed
-/// revision hash against the <see cref="ITemplateGraphWatermark"/> readings it was
-/// computed under, and the memo is PROCESS-STATIC. That makes the watermark the
-/// only thing standing between a cached hash and a wrong answer — so these tests
-/// pin that the memo is served only while the watermark has not moved, and is
-/// dropped the moment it has.
-///
-/// <para>
-/// The failure this guards against is a real one: a data-connection edit, or a
-/// bundle import committing through the raw <c>DbContext</c>, changes the flattened
-/// output without going through the repository path that derives bumps from the
-/// change tracker. If that write does not bump, the memo below keeps answering with
-/// the old hash forever.
-/// </para>
+/// <see cref="StaleInstanceProbe"/> is authoritative: it re-flattens on EVERY probe and
+/// memoises nothing across calls. It used to memoise a revision hash against the
+/// process-local <see cref="ITemplateGraphWatermark"/>, which a peer central node writing
+/// the shared database could never bump (MG-3) — these tests pin that every probe sees
+/// the current configuration whatever the local watermark says.
 /// </summary>
 public class StaleInstanceProbeTests
 {
@@ -35,9 +26,6 @@ public class StaleInstanceProbeTests
     /// <summary>Initializes a new instance of the <c>StaleInstanceProbeTests</c> class.</summary>
     public StaleInstanceProbeTests()
     {
-        // Process-static memo: start every test from a clean slate.
-        StaleInstanceProbe.ClearMemos();
-
         _pipeline.CreateSession().Returns(_ => new FlattenSession(_watermark));
         _pipeline
             .FlattenAndValidateAsync(InstanceId, Arg.Any<CancellationToken>(), Arg.Any<bool>(), Arg.Any<FlattenSession?>())
@@ -50,7 +38,20 @@ public class StaleInstanceProbeTests
             });
     }
 
-    private StaleInstanceProbe CreateProbe() => new(_pipeline, _watermark);
+    private StaleInstanceProbe CreateProbe() => new(_pipeline);
+
+    /// <summary>
+    /// review 2026-10-21 04/U2: with the memo gone the probe has no use for the watermark, so
+    /// its only dependency is the pipeline and the no-op <c>ClearMemos</c> hook is gone.
+    /// </summary>
+    [Fact]
+    public void Probe_DependsOnlyOnThePipeline_AndHasNoMemoHook()
+    {
+        var ctor = Assert.Single(typeof(StaleInstanceProbe).GetConstructors());
+        var parameter = Assert.Single(ctor.GetParameters());
+        Assert.Equal(typeof(IFlatteningPipeline), parameter.ParameterType);
+        Assert.Null(typeof(StaleInstanceProbe).GetMethod("ClearMemos"));
+    }
 
     /// <summary>Verifies that peer edit with independent watermark is observed by warm active probe.</summary>
     /// <returns>A task that represents the asynchronous operation.</returns>
diff --git a/tests/ZB.MOM.WW.ScadaBridge.Transport.IntegrationTests/Import/BundleImporterApplyTests.cs b/tests/ZB.MOM.WW.ScadaBridge.Transport.IntegrationTests/Import/BundleImporterApplyTests.cs
index 8716b988..fcabceb6 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.Transport.IntegrationTests/Import/BundleImporterApplyTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.Transport.IntegrationTests/Import/BundleImporterApplyTests.cs
@@ -1595,10 +1595,6 @@ public sealed class BundleImporterApplyTests : IDisposable
     [Fact]
     public async Task ApplyAsync_second_overwrite_of_same_template_still_marks_instance_stale()
     {
-        // The memo is process-static and keyed by instance id alone; start clean so
-        // this test does not inherit another class's entry.
-        StaleInstanceProbe.ClearMemos();
-
         await SeedSiteAsync();
 
         // Shape A → bundle A.