diff --git a/ReleaseNotes.md b/ReleaseNotes.md
index 7ab9398e7..acee13379 100644
--- a/ReleaseNotes.md
+++ b/ReleaseNotes.md
@@ -1,4 +1,4 @@
-# 3.0.454 (Caba series release 9)
+# 3.0.455 (Caba series release 9)
 * `-o|outputFile` option in `runner` mode (parameter `OutputFile` for the `AltCover.Collect` task) to allow the default report for the current dataset to be written to a new file, rather than updating/accumulating in the file specified at instrumentation time.
 * Some refactoring and adjustements to the build processes
 * [BUGFIX] -- handle and signal exceptions in the visit recording, rather than potentially just locking up or silently failing
diff --git a/Shadow.Tests/Shadow.Tests.fs b/Shadow.Tests/Shadow.Tests.fs
index 124c94c78..0bae0b197 100644
--- a/Shadow.Tests/Shadow.Tests.fs
+++ b/Shadow.Tests/Shadow.Tests.fs
@@ -541,6 +541,8 @@ type AltCoverTests() = class
         Instance.FlushCounter ProcessExit ()
         while Instance.Backlog () > 0 do
           Thread.Sleep 100
+
+        Thread.Sleep 100
         Assert.That(Instance.mailboxOK, Is.False)
 
         // Restart the mailbox