Only one failure so far but the stack seemed pretty definitive here so filing the issue.
System.Net.Security.Tests.ApmSslStreamSystemDefaultTest.ClientAndServer_OneOrBothUseDefault_Ok(clientProtocols: Default, serverProtocols: Ssl2 | Default | Tls11 | Tls12) [FAIL]
System.ObjectDisposedException : Safe handle has been closed.
Object name: 'SafeHandle'.
Stack Trace:
/_/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/SafeHandle.cs(149,0): at System.Runtime.InteropServices.SafeHandle.DangerousAddRef(Boolean& success)
/_/src/libraries/Common/src/Interop/Windows/SspiCli/SecuritySafeHandles.cs(354,0): at System.Net.Security.SafeCredentialReference..ctor(SafeFreeCredentials target)
/_/src/libraries/Common/src/Interop/Windows/SspiCli/SecuritySafeHandles.cs(341,0): at System.Net.Security.SafeCredentialReference.CreateReference(SafeFreeCredentials target)
/_/src/libraries/System.Net.Security/src/System/Net/Security/SslSessionsCache.cs(201,0): at System.Net.Security.SslSessionsCache.CacheCredential(SafeFreeCredentials creds, Byte[] thumbPrint, SslProtocols sslProtocols, Boolean isServer, EncryptionPolicy encryptionPolicy)
/_/src/libraries/System.Net.Security/src/System/Net/Security/SecureChannel.cs(830,0): at System.Net.Security.SecureChannel.GenerateToken(ReadOnlySpan`1 inputBuffer, Byte[]& output)
/_/src/libraries/System.Net.Security/src/System/Net/Security/SecureChannel.cs(726,0): at System.Net.Security.SecureChannel.NextMessage(ReadOnlySpan`1 incomingBuffer)
at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)
/_/src/libraries/Common/src/System/Threading/Tasks/TaskToApm.cs(42,0): at System.Threading.Tasks.TaskToApm.End(IAsyncResult asyncResult)
/_/src/libraries/System.Net.Security/src/System/Net/Security/SslStream.cs(233,0): at System.Net.Security.SslStream.EndAuthenticateAsClient(IAsyncResult asyncResult)
/_/src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs(513,0): at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location ---
/_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(83,0): at System.Threading.Tasks.TaskTimeoutExtensions.WhenAllOrAnyFailed(Task[] tasks)
/_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(111,0): at System.Threading.Tasks.TaskTimeoutExtensions.WhenAllOrAnyFailed(Task[] tasks)
/_/src/libraries/Common/tests/System/Threading/Tasks/TaskTimeoutExtensions.cs(71,0): at System.Threading.Tasks.TaskTimeoutExtensions.WhenAllOrAnyFailed(Task[] tasks, Int32 millisecondsTimeout)
/_/src/libraries/System.Net.Security/tests/FunctionalTests/SslStreamSystemDefaultsTest.cs(60,0): at System.Net.Security.Tests.SslStreamSystemDefaultTest.ClientAndServer_OneOrBothUseDefault_Ok(Nullable`1 clientProtocols, Nullable`1 serverProtocols)
--- End of stack trace from previous location ---
