diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipConnection.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipConnection.cs
index a9754706..d9508a81 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipConnection.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipConnection.cs
@@ -123,7 +123,14 @@ public sealed class CipConnection : ICipChannel, IAsyncDisposable
             }
             pending = _pendingOpen;
         }
-        if (started is not null) _ = RunOpenAsync(started);
+        if (started is not null)
+        {
+            // Every waiter may have abandoned the open (its own token); observe a failure so it never
+            // surfaces as UnobservedTaskException.
+            _ = started.Task.ContinueWith(static t => _ = t.Exception, CancellationToken.None,
+                TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
+            _ = RunOpenAsync(started);
+        }
         return pending.WaitAsync(ct);
     }
 
@@ -170,6 +177,12 @@ public sealed class CipConnection : ICipChannel, IAsyncDisposable
     {
         ThrowIfDisposed();   // disposal may have begun while this attempt waited out the throttle
         var client = await EncapsulationClient.ConnectAsync(_key.Host, _key.Port, _o.Timeout, ct).ConfigureAwait(false);
+        if (Volatile.Read(ref _disposed) != 0)
+        {
+            // Disposal began during the TCP connect / RegisterSession: never put a Forward Open on the wire.
+            await client.DisposeAsync().ConfigureAwait(false);
+            throw new AbTransportException(AbStatus.Abort, "Connection disposed.");
+        }
         if (_o.Routing != CipRouting.Connected) return new Open(client, null, 0, UnconnectedMessageLimit);
         try
         {
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipPath.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipPath.cs
index e653a932..058176aa 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipPath.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipPath.cs
@@ -17,6 +17,10 @@ public static class CipPath
         {
             var port = int.Parse(parts[i], CultureInfo.InvariantCulture);
             var link = parts[i + 1];
+            // A link is a slot byte or an IP address/hostname; neither contains whitespace. Without this a
+            // typo like "1,2 3" would be sent as an ASCII link "2 3" instead of failing here.
+            if (link.Length == 0 || link.Any(char.IsWhiteSpace))
+                throw new ArgumentException($"CIP path '{cipPath}' has an empty or malformed link '{link}'.", nameof(cipPath));
             var isByte = byte.TryParse(link, NumberStyles.None, CultureInfo.InvariantCulture, out var linkByte);
             if (port < 15)
             {
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/DeviceKey.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/DeviceKey.cs
index 9756d613..c8331d21 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/DeviceKey.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/DeviceKey.cs
@@ -3,14 +3,16 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Cip;
 /// <summary>
 /// Identity of one physical CIP connection: exactly one <see cref="CipConnection"/> (and one Forward Open
 /// throttle) exists per key (press safety). <see cref="Host"/> and <see cref="PlcAttribute"/> compare
-/// case-insensitively; <see cref="Port"/> compares exactly; <see cref="CipPath"/> is canonicalised (all
-/// whitespace removed, so <c>"1,0"</c> and <c>" 1, 0 "</c> are the same device) and then compares exactly.
+/// case-insensitively; <see cref="Port"/> compares exactly; <see cref="CipPath"/> is canonicalised (each
+/// comma-separated part trimmed, so <c>"1,0"</c> and <c>" 1, 0 "</c> are the same device) and then
+/// compares exactly. Whitespace INSIDE a part is kept, so a typo such as <c>"1,2 3"</c> still fails loudly in
+/// <see cref="Cip.CipPath.EncodeRoute"/> instead of silently becoming slot 23.
 /// </summary>
 public sealed record DeviceKey(string Host, int Port, string CipPath, string PlcAttribute)
 {
     private readonly string _cipPath = Canonicalise(CipPath);
 
-    /// <summary>The route, whitespace-free. Canonicalised on construction and on <c>with</c>.</summary>
+    /// <summary>The route with each part trimmed. Canonicalised on construction and on <c>with</c>.</summary>
     public string CipPath
     {
         get => _cipPath;
@@ -18,7 +20,7 @@ public sealed record DeviceKey(string Host, int Port, string CipPath, string Plc
     }
 
     private static string Canonicalise(string? path) =>
-        path is null ? "" : string.Concat(path.Where(c => !char.IsWhiteSpace(c)));
+        string.IsNullOrWhiteSpace(path) ? "" : string.Join(',', path.Split(',').Select(p => p.Trim()));
 
     public bool Equals(DeviceKey? other) =>
         other is not null
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/ForwardOpenThrottle.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/ForwardOpenThrottle.cs
index 778f1995..b315aa06 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/ForwardOpenThrottle.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/ForwardOpenThrottle.cs
@@ -24,9 +24,12 @@ public sealed class ForwardOpenThrottle
         _time = time ?? throw new ArgumentNullException(nameof(time));
     }
 
-    /// <summary>Run one open attempt once the throttle allows it. Throws
-    /// <see cref="AbTransportException"/>(<see cref="AbStatus.BadConnection"/>) when <paramref name="ct"/>
-    /// fires before the attempt could start; the attempt itself sees <paramref name="ct"/> too.</summary>
+    /// <summary>Run one open attempt once the throttle allows it. <paramref name="ct"/> bounds only the wait
+    /// BEFORE the attempt (queued behind an in-flight attempt, or the interval): when it fires there, this
+    /// throws <see cref="AbTransportException"/>(<see cref="AbStatus.BadConnection"/>, "Forward Open
+    /// throttled"). <paramref name="ct"/> is also passed to <paramref name="open"/>, which may ignore it:
+    /// <see cref="CipConnection"/> does, running the attempt under its own open deadline so that an accepted
+    /// Forward Open is never abandoned without a Forward Close.</summary>
     public async Task<T> RunAsync<T>(Func<CancellationToken, Task<T>> open, CancellationToken ct)
     {
         ArgumentNullException.ThrowIfNull(open);
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/DeviceSessionPoolTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/DeviceSessionPoolTests.cs
index d9cdb478..bf14ebf9 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/DeviceSessionPoolTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/DeviceSessionPoolTests.cs
@@ -162,6 +162,7 @@ public sealed class DeviceSessionPoolTests
         b.ShouldBe(a);
         b.GetHashCode().ShouldBe(a.GetHashCode());
         (a with { CipPath = "1, 2" }).CipPath.ShouldBe("1,2");
+        new DeviceKey("plc1", 44818, "   ", "ControlLogix").CipPath.ShouldBe("");
 
         var pool = new DeviceSessionPool(new ManualTimeProvider());
         await using var la = pool.Acquire(a, Options());
@@ -170,6 +171,16 @@ public sealed class DeviceSessionPoolTests
         pool.EntryCount.ShouldBe(1);
     }
 
+    [Fact]
+    public void Whitespace_inside_a_cip_path_part_is_kept_so_a_typo_fails_loudly()
+    {
+        var typo = new DeviceKey("plc1", 44818, "1,2 3", "ControlLogix");
+        typo.CipPath.ShouldNotBe("1,23");                    // never silently slot 23 on another controller
+        typo.CipPath.ShouldBe("1,2 3");
+        Should.Throw<ArgumentException>(() => CipPath.EncodeRoute(typo.CipPath));
+        CipPath.EncodeRoute(new DeviceKey("plc1", 44818, " 1, 0 ", "ControlLogix").CipPath).ShouldBe(new byte[] { 0x01, 0x00 });
+    }
+
     [Fact]
     public async Task A_new_connection_waits_for_every_earlier_close_not_just_the_latest()
     {