diff --git a/Capnp.Net.Runtime.Tests/Mock/TestCapImplementations.cs b/Capnp.Net.Runtime.Tests/Mock/TestCapImplementations.cs
index 795d451..3c5093e 100644
--- a/Capnp.Net.Runtime.Tests/Mock/TestCapImplementations.cs
+++ b/Capnp.Net.Runtime.Tests/Mock/TestCapImplementations.cs
@@ -421,9 +421,12 @@ namespace Capnp.Net.Runtime.Tests.GenImpls
         public void Dispose()
         {
             _tcs?.TrySetResult(0);
+            Assert.IsFalse(IsDisposed);
             IsDisposed = true;
+            DisposeCallStack = Environment.StackTrace;
         }
 
+        public string DisposeCallStack { get; private set; }
         public bool IsDisposed { get; private set; }
 
         public virtual Task<string> Foo(uint i, bool j, CancellationToken cancellationToken)
@@ -836,6 +839,7 @@ namespace Capnp.Net.Runtime.Tests.GenImpls
         public void Dispose()
         {
             ClientToHold?.Dispose();
+            ClientToHold = null;
         }
 
         public Task<ITestCallOrder> Echo(ITestCallOrder cap, CancellationToken cancellationToken_)
diff --git a/Capnp.Net.Runtime.Tests/Testsuite.cs b/Capnp.Net.Runtime.Tests/Testsuite.cs
index a888d65..77e0a59 100644
--- a/Capnp.Net.Runtime.Tests/Testsuite.cs
+++ b/Capnp.Net.Runtime.Tests/Testsuite.cs
@@ -311,7 +311,7 @@ namespace Capnp.Net.Runtime.Tests
 
                 using (var claimer = Skeleton.Claim(cap))
                 {
-                    var ftask = main.CallFoo(cap, default);
+                    var ftask = main.CallFoo(Proxy.Share<ITestInterface>(cap), default);
                     testbed.MustComplete(ftask);
                     Assert.AreEqual("bar", ftask.Result);
 
@@ -319,8 +319,8 @@ namespace Capnp.Net.Runtime.Tests
                     testbed.MustComplete(ctask);
                     Assert.AreEqual(1u, ctask.Result);
 
-                    ftask1 = main.CallFoo(cap, default);
-                    ftask2 = main.CallFoo(cap, default);
+                    ftask1 = main.CallFoo(Proxy.Share<ITestInterface>(cap), default);
+                    ftask2 = main.CallFoo(Proxy.Share<ITestInterface>(cap), default);
                 }
 
                 testbed.MustComplete(ftask1);
@@ -804,18 +804,20 @@ namespace Capnp.Net.Runtime.Tests
 
         public static void ReexportSenderPromise(ITestbed testbed)
         {
-            var impl = new TestTailCallerImpl(new Counters());
-            using (var main = testbed.ConnectMain<ITestTailCaller>(impl))
+            var impl = new TestMoreStuffImpl(new Counters());
+            using (var main = testbed.ConnectMain<ITestMoreStuff>(impl))
             {
-                var tcs = new TaskCompletionSource<ITestTailCallee>();
-                using (var promise = Proxy.Share(tcs.Task.Eager(true)))
+                var tcs = new TaskCompletionSource<ITestInterface>();
+                var tcsd = new TaskCompletionSource<int>();
+                using (var promise = tcs.Task.Eager(true))
                 {
-                    var task1 = main.Foo(1, Proxy.Share(promise));
-                    var task2 = main.Foo(2, Proxy.Share(promise));
-                    var callee = new TestTailCalleeImpl(new Counters());
+                    var task1 = main.CallFooWhenResolved(Proxy.Share(promise));
+                    var task2 = main.CallFooWhenResolved(Proxy.Share(promise));
+                    var callee = new TestInterfaceImpl(new Counters(), tcsd);
                     tcs.SetResult(callee);
                     testbed.MustComplete(task1, task2);
                 }
+                testbed.MustComplete(tcsd.Task);
             }
         }
     }
diff --git a/Capnp.Net.Runtime.Tests/Util/TestBase.cs b/Capnp.Net.Runtime.Tests/Util/TestBase.cs
index e40b7a1..5f13b70 100644
--- a/Capnp.Net.Runtime.Tests/Util/TestBase.cs
+++ b/Capnp.Net.Runtime.Tests/Util/TestBase.cs
@@ -161,7 +161,7 @@ namespace Capnp.Net.Runtime.Tests
 
             T ITestbed.ConnectMain<T>(object main)
             {
-                return (T)main;
+                return Proxy.Share<T>((T)main);
             }
 
             void ITestbed.FlushCommunication()
diff --git a/Capnp.Net.Runtime/Rpc/PolySkeleton.cs b/Capnp.Net.Runtime/Rpc/PolySkeleton.cs
index 17def26..c7762dd 100644
--- a/Capnp.Net.Runtime/Rpc/PolySkeleton.cs
+++ b/Capnp.Net.Runtime/Rpc/PolySkeleton.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -54,7 +55,8 @@ namespace Capnp.Rpc
         /// </summary>
         protected override void Dispose(bool disposing)
         {
-            foreach (var cap in _ifmap.Values)
+            foreach (var cap in _ifmap.Values.Take(1))
+            // releasing first skeleton is sufficient. Avoid double-Dispose!
             {
                 cap.Relinquish();
             }
@@ -64,7 +66,7 @@ namespace Capnp.Rpc
 
         internal override void Bind(object impl)
         {
-            foreach (Skeleton skel in _ifmap.Values)
+            foreach (Skeleton skel in _ifmap.Values) 
             {
                 skel.Bind(impl);
             }
diff --git a/Capnp.Net.Runtime/Rpc/Proxy.cs b/Capnp.Net.Runtime/Rpc/Proxy.cs
index de67ab1..f82b6e0 100644
--- a/Capnp.Net.Runtime/Rpc/Proxy.cs
+++ b/Capnp.Net.Runtime/Rpc/Proxy.cs
@@ -154,14 +154,14 @@ namespace Capnp.Rpc
             {
                 if (disposing)
                 {
-                    _consumedCap?.Release();
+                    _consumedCap.Release();
                 }
                 else
                 {
                     // When called from the Finalizer, we must not throw.
                     // But when reference counting goes wrong, ConsumedCapability.Release() will throw an InvalidOperationException.
                     // The only option here is to suppress that exception.
-                    try { _consumedCap?.Release(); }
+                    try { _consumedCap.Release(); }
                     catch { }
                 }