Fix failed event script double setting a TaskCompletionSource

build/Version.props

@@ -3,7 +3,7 @@
   <!-- Integration tests will ensure they match across the board -->
   <Import Project="WebpanelVersion.props" />
   <PropertyGroup>
-    <TgsCoreVersion>6.12.0</TgsCoreVersion>
+    <TgsCoreVersion>6.11.4</TgsCoreVersion>
     <TgsConfigVersion>5.4.0</TgsConfigVersion>
     <TgsRestVersion>10.12.0</TgsRestVersion>
     <TgsGraphQLVersion>0.5.0</TgsGraphQLVersion>

src/Tgstation.Server.Host/Components/Engine/EngineManager.cs

@@ -477,9 +477,9 @@ namespace Tgstation.Server.Host.Components.Engine
 
 					await InstallVersionFiles(progressReporter, version, customVersionStream, deploymentPipelineProcesses, cancellationToken);
 
-					ourTcs.SetResult();
-
 					await eventConsumer.HandleEvent(EventType.EngineInstallComplete, new List<string> { versionString }, deploymentPipelineProcesses, cancellationToken);
+
+					ourTcs.SetResult();
 				}
 				catch (Exception ex)
 				{