diff --git a/docs/requirements/Component-ManagementService.md b/docs/requirements/Component-ManagementService.md
index 83ded24c..38b1b7e7 100644
--- a/docs/requirements/Component-ManagementService.md
+++ b/docs/requirements/Component-ManagementService.md
@@ -192,6 +192,7 @@ The two-person authorization workflow for writes through the MxAccess Gateway. B
 - **ListApiKeys** / **CreateApiKey** / **UpdateApiKey** / **EnableApiKey** / **DisableApiKey** / **DeleteApiKey**: Manage API keys.
 - **ListRoleMappings** / **CreateRoleMapping** / **UpdateRoleMapping** / **DeleteRoleMapping**: Manage LDAP group-to-role mappings.
 - **ListScopeRules** / **AddScopeRule** / **DeleteScopeRule**: Manage site scope rules on role mappings.
+- Every role-mapping and scope-rule mutation (Create/Update/DeleteRoleMapping, Add/DeleteScopeRule) calls `RoleMappingCache.Invalidate()` as a **post-commit** action, so the change takes effect for the next role mapping on the node that served the command instead of after the `RoleMappingCacheSeconds` TTL (default 30 s); the other central node still converges within that TTL. Post-commit, because invalidating inside the transaction would let a concurrent mapping re-cache the pre-change table.
 
 ### Audit Log
 
diff --git a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
index 57cc52f7..1ea6c920 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
@@ -2820,6 +2820,21 @@ public class ManagementActor : ReceiveActor
             $"Role '{role}' is not a recognized role. Valid roles are: {string.Join(", ", Roles.All)}.");
     }
 
+    /// <summary>
+    /// Drops this node's <see cref="RoleMappingCache"/> snapshot once a mapping / scope-rule
+    /// change has committed, so the next role mapping on this node sees it immediately rather
+    /// than after the cache TTL (lane K review M1). Queued post-commit: invalidating before the
+    /// commit would let a concurrent mapping re-cache the pre-change table. Other central
+    /// nodes still converge within <c>RoleMappingCacheSeconds</c>.
+    /// </summary>
+    private static Task InvalidateRoleMappingCacheAfterCommit(IServiceProvider sp)
+    {
+        var cache = sp.GetService<RoleMappingCache>();
+        return cache is null
+            ? Task.CompletedTask
+            : AfterConfigurationCommit(sp, () => { cache.Invalidate(); return Task.CompletedTask; });
+    }
+
     private static async Task<object?> HandleCreateRoleMapping(IServiceProvider sp, CreateRoleMappingCommand cmd, string user)
     {
         var role = CanonicalizeMappingRole(cmd.Role);
@@ -2827,6 +2842,7 @@ public class ManagementActor : ReceiveActor
         var mapping = new LdapGroupMapping(cmd.LdapGroupName, role);
         await repo.AddMappingAsync(mapping);
         await repo.SaveChangesAsync();
+        await InvalidateRoleMappingCacheAfterCommit(sp);
         await AuditAsync(sp, user, "Create", "RoleMapping", mapping.Id.ToString(), $"{mapping.LdapGroupName}->{mapping.Role}", mapping);
         return mapping;
     }
@@ -2841,6 +2857,7 @@ public class ManagementActor : ReceiveActor
         mapping.Role = role;
         await repo.UpdateMappingAsync(mapping);
         await repo.SaveChangesAsync();
+        await InvalidateRoleMappingCacheAfterCommit(sp);
         await AuditAsync(sp, user, "Update", "RoleMapping", mapping.Id.ToString(), $"{mapping.LdapGroupName}->{mapping.Role}", mapping);
         return mapping;
     }
@@ -2850,6 +2867,7 @@ public class ManagementActor : ReceiveActor
         var repo = sp.GetRequiredService<ISecurityRepository>();
         await repo.DeleteMappingAsync(cmd.MappingId);
         await repo.SaveChangesAsync();
+        await InvalidateRoleMappingCacheAfterCommit(sp);
         await AuditAsync(sp, user, "Delete", "RoleMapping", cmd.MappingId.ToString(), cmd.MappingId.ToString(), null);
         return true;
     }
@@ -3807,6 +3825,7 @@ public class ManagementActor : ReceiveActor
         var rule = new SiteScopeRule { LdapGroupMappingId = cmd.MappingId, SiteId = cmd.SiteId };
         await repo.AddScopeRuleAsync(rule);
         await repo.SaveChangesAsync();
+        await InvalidateRoleMappingCacheAfterCommit(sp);
         await AuditAsync(sp, user, "Create", "ScopeRule", rule.Id.ToString(), $"Mapping:{cmd.MappingId}/Site:{cmd.SiteId}", rule);
         return rule;
     }
@@ -3816,6 +3835,7 @@ public class ManagementActor : ReceiveActor
         var repo = sp.GetRequiredService<ISecurityRepository>();
         await repo.DeleteScopeRuleAsync(cmd.ScopeRuleId);
         await repo.SaveChangesAsync();
+        await InvalidateRoleMappingCacheAfterCommit(sp);
         await AuditAsync(sp, user, "Delete", "ScopeRule", cmd.ScopeRuleId.ToString(), cmd.ScopeRuleId.ToString(), null);
         return true;
     }
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/RoleMappingCacheInvalidationTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/RoleMappingCacheInvalidationTests.cs
new file mode 100644
index 00000000..42e758bd
--- /dev/null
+++ b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/RoleMappingCacheInvalidationTests.cs
@@ -0,0 +1,87 @@
+using Akka.Actor;
+using Akka.TestKit.Xunit2;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging.Abstractions;
+using NSubstitute;
+using ZB.MOM.WW.ScadaBridge.Commons.Entities.Security;
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
+using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
+using ZB.MOM.WW.ScadaBridge.Security;
+
+namespace ZB.MOM.WW.ScadaBridge.ManagementService.Tests;
+
+/// <summary>
+/// Lane K review M1: the process-wide <see cref="RoleMappingCache"/> served a deleted or
+/// changed LDAP-group mapping for up to its TTL on the node that made the change. Every
+/// role-mapping / scope-rule mutation now invalidates it once the change is committed.
+/// </summary>
+public class RoleMappingCacheInvalidationTests : TestKit
+{
+    private readonly ISecurityRepository _repo = Substitute.For<ISecurityRepository>();
+    private readonly RoleMappingCache _cache = new(TimeProvider.System);
+    private readonly ServiceCollection _services = new ServiceCollection().AddTestConfigurationTransaction();
+    private List<LdapGroupMapping> _mappings = [new("Ops", "Deployer") { Id = 5 }];
+
+    /// <summary>Initializes the harness with one Deployer mapping for group "Ops".</summary>
+    public RoleMappingCacheInvalidationTests()
+    {
+        _repo.GetAllMappingsAsync(Arg.Any<CancellationToken>()).Returns(_ => _mappings);
+        _repo.GetScopeRulesForMappingAsync(Arg.Any<int>(), Arg.Any<CancellationToken>())
+            .Returns(new List<SiteScopeRule>());
+        _repo.GetMappingByIdAsync(5, Arg.Any<CancellationToken>()).Returns(_ => _mappings.FirstOrDefault());
+        _services.AddScoped(_ => _repo);
+        _services.AddScoped(_ => Substitute.For<IAuditService>());
+        _services.AddSingleton(_cache);
+    }
+
+    private IActorRef CreateActor() =>
+        Sys.ActorOf(Props.Create(() => new ManagementActor(
+            _services.BuildServiceProvider(), NullLogger<ManagementActor>.Instance)));
+
+    private static ManagementEnvelope Admin(object command) =>
+        new(new AuthenticatedUser("admin", "Admin", new[] { "Administrator" }, Array.Empty<string>()),
+            command, Guid.NewGuid().ToString("N"));
+
+    private Task<RoleMappingResult> MapOps() => new RoleMapper(_repo, _cache).MapGroupsToRolesAsync(["Ops"]);
+
+    /// <summary>A deleted mapping is visible to the very next mapping on the same cache.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [Fact]
+    public async Task DeleteRoleMapping_IsVisibleToTheNextMapping()
+    {
+        Assert.Contains("Deployer", (await MapOps()).Roles); // primes the snapshot
+
+        _mappings = [];
+        CreateActor().Tell(Admin(new DeleteRoleMappingCommand(5)));
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+
+        Assert.Empty((await MapOps()).Roles);
+    }
+
+    /// <summary>Every mapping / scope-rule mutation invalidates the snapshot.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [Fact]
+    public async Task EveryMappingMutation_InvalidatesTheSnapshot()
+    {
+        object[] commands =
+        [
+            new CreateRoleMappingCommand("Eng", "Designer"),
+            new UpdateRoleMappingCommand(5, "Ops", "Viewer"),
+            new AddScopeRuleCommand(5, 2),
+            new DeleteScopeRuleCommand(9),
+        ];
+        var actor = CreateActor();
+        foreach (var command in commands)
+        {
+            await MapOps(); // prime
+            _repo.ClearReceivedCalls();
+
+            actor.Tell(Admin(command));
+            ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+
+            await MapOps();
+            await _repo.Received(1).GetAllMappingsAsync(Arg.Any<CancellationToken>()); // re-read, not served stale
+        }
+    }
+}