diff --git a/src/libraries/Common/tests/System/Net/Http/Http3LoopbackConnection.cs b/src/libraries/Common/tests/System/Net/Http/Http3LoopbackConnection.cs
index 581bc018a1983..a8e18ae6fce78 100644
--- a/src/libraries/Common/tests/System/Net/Http/Http3LoopbackConnection.cs
+++ b/src/libraries/Common/tests/System/Net/Http/Http3LoopbackConnection.cs
@@ -315,8 +315,11 @@ public async Task WaitForClientDisconnectAsync(bool refuseNewRequests = true)
 
             // The client's control stream should throw QuicConnectionAbortedException, indicating that it was
             // aborted because the connection was closed (and was not explicitly closed or aborted prior to the connection being closed)
-            QuicException ex = await Assert.ThrowsAsync<QuicException>(async () => await _inboundControlStream.ReadFrameAsync().ConfigureAwait(false));
-            Assert.Equal(QuicError.ConnectionAborted, ex.QuicError);
+            if (_inboundControlStream is not null)
+            {
+                QuicException ex = await Assert.ThrowsAsync<QuicException>(async () => await _inboundControlStream.ReadFrameAsync().ConfigureAwait(false));
+                Assert.Equal(QuicError.ConnectionAborted, ex.QuicError);
+            }
 
             await CloseAsync(H3_NO_ERROR).ConfigureAwait(false);
         }
diff --git a/src/libraries/System.Net.Http/tests/FunctionalTests/DiagnosticsTests.cs b/src/libraries/System.Net.Http/tests/FunctionalTests/DiagnosticsTests.cs
index 8da624c76fd86..77b8893318343 100644
--- a/src/libraries/System.Net.Http/tests/FunctionalTests/DiagnosticsTests.cs
+++ b/src/libraries/System.Net.Http/tests/FunctionalTests/DiagnosticsTests.cs
@@ -237,12 +237,6 @@ await RemoteExecutor.Invoke(async (useVersion, testAsync) =>
         [ConditionalFact(typeof(RemoteExecutor), nameof(RemoteExecutor.IsSupported))]
         public async Task SendAsync_ExpectedDiagnosticCancelledLogging()
         {
-            if (UseVersion == HttpVersion30)
-            {
-                // [ActiveIssue("https://github.com/dotnet/runtime/issues/104699")]
-                throw new SkipTestException("SendAsync_ExpectedDiagnosticCancelledLogging is broken on HTTP/3.");
-            }
-
             await RemoteExecutor.Invoke(async (useVersion, testAsync) =>
             {
                 TaskCompletionSource responseLoggedTcs = new(TaskCreationOptions.RunContinuationsAsynchronously);