diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
index 9e6091e9..6f536cb0 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
@@ -458,6 +458,15 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                     advertised.Count, source.GetType().Name,
                     string.Join(", ", advertised.Select(id => AggregateFunctionMap.Map(id)?.ToString() ?? id.ToString())));
             }
+
+            // #736: HistoryServerCapabilities/MaxReturnDataValues (i=11273) carries the source's raw-page cap
+            // (0 = unlimited), re-synced on every source assignment like the aggregate set above.
+            if (!HistoryPaging.AdvertiseMaxReturnDataValues(Server, source.MaxRawValuesPerRead))
+            {
+                _logger.LogWarning(
+                    "OtOpcUaNodeManager: could not advertise HistoryServerCapabilities/MaxReturnDataValues ({Cap}) for historian {Source}; the cap is still enforced by HistoryRead",
+                    source.MaxRawValuesPerRead, source.GetType().Name);
+            }
         }
         catch (Exception ex)
         {
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerMaxReturnDataValuesSyncTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerMaxReturnDataValuesSyncTests.cs
new file mode 100644
index 00000000..ea47eedd
--- /dev/null
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerMaxReturnDataValuesSyncTests.cs
@@ -0,0 +1,67 @@
+using Opc.Ua;
+using Opc.Ua.Server;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using HistorianRead = ZB.MOM.WW.OtOpcUa.Core.Abstractions.HistoryReadResult;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     #736 — assigning <see cref="OtOpcUaNodeManager.HistorianDataSource"/> re-syncs
+///     <c>HistoryServerCapabilities/MaxReturnDataValues</c> (i=11273) to the source's
+///     <see cref="IHistorianDataSource.MaxRawValuesPerRead"/>, read back the way a client would. The Null
+///     source (the historian-disabled default) advertises Part 11's "no limit".
+/// </summary>
+public sealed class NodeManagerMaxReturnDataValuesSyncTests(BoundsServerFixture fx) : IClassFixture<BoundsServerFixture>
+{
+    [Fact]
+    public async Task Setting_the_historian_source_advertises_its_raw_cap()
+    {
+        await fx.Gate.WaitAsync(TestContext.Current.CancellationToken);
+        try
+        {
+            fx.Nm.HistorianDataSource = new CappedSource(7_000);
+            (await ReadAdvertisedAsync()).ShouldBe(7_000u);
+
+            fx.Nm.HistorianDataSource = new CappedSource(250);
+            (await ReadAdvertisedAsync()).ShouldBe(250u);
+
+            fx.Nm.HistorianDataSource = null!; // the Null default: no cap
+            (await ReadAdvertisedAsync()).ShouldBe(0u);
+        }
+        finally
+        {
+            fx.Nm.HistorianDataSource = null!;
+            fx.Gate.Release();
+        }
+    }
+
+    private async Task<uint> ReadAdvertisedAsync()
+    {
+        var context = new OperationContext(new RequestHeader(), secureChannelContext: null, RequestType.Read, identity: null);
+        var nodesToRead = new ReadValueIdCollection
+        {
+            new ReadValueId { NodeId = VariableIds.HistoryServerCapabilities_MaxReturnDataValues, AttributeId = Attributes.Value },
+        };
+        var (values, _) = await fx.Nm.Server.NodeManager.ReadAsync(context, 0, TimestampsToReturn.Neither, nodesToRead, TestContext.Current.CancellationToken);
+        values.Count.ShouldBe(1);
+        StatusCode.IsGood(values[0].StatusCode).ShouldBeTrue(values[0].StatusCode.ToString());
+        return (uint)values[0].Value;
+    }
+
+    private sealed class CappedSource(int cap) : IHistorianDataSource
+    {
+        public int MaxRawValuesPerRead => cap;
+        public Task<HistorianRead> ReadRawAsync(string r, DateTime s, DateTime e, uint m, CancellationToken ct) =>
+            NullHistorianDataSource.Instance.ReadRawAsync(r, s, e, m, ct);
+        public Task<HistorianRead> ReadProcessedAsync(string r, DateTime s, DateTime e, TimeSpan i, HistoryAggregateType a, CancellationToken ct) =>
+            NullHistorianDataSource.Instance.ReadProcessedAsync(r, s, e, i, a, ct);
+        public Task<HistorianRead> ReadAtTimeAsync(string r, IReadOnlyList<DateTime> t, CancellationToken ct) =>
+            NullHistorianDataSource.Instance.ReadAtTimeAsync(r, t, ct);
+        public Task<HistoricalEventsResult> ReadEventsAsync(string? n, DateTime s, DateTime e, int m, CancellationToken ct) =>
+            NullHistorianDataSource.Instance.ReadEventsAsync(n, s, e, m, ct);
+        public HistorianHealthSnapshot GetHealthSnapshot() => NullHistorianDataSource.Instance.GetHealthSnapshot();
+        public void Dispose() { }
+    }
+}