Blazor integration in ASP.NET MVC causes button and link actions to be executed twice

[KevinMartins84]

Is there an existing issue for this?

• [x] I have searched the existing issues

Describe the bug

When integrating Blazor components into an existing ASP.NET MVC project following the official Blazor integration guide, I encountered an issue where actions like link and button clicks are executed twice. This happens when both regular MVC and Blazor components exist on the same page, and the _blazor.js script is included.

I observed this behavior using Chrome DevTools, where each click resulted in two network requests for the same action. This occurs even in a clean new MVC project with Blazor support added, following the tutorial.

Expected Behavior

Clicking on links or buttons should trigger the action only once, without interference from Blazor on regular MVC actions.

Steps To Reproduce

Create a new ASP.NET MVC project. Follow the official tutorial to add Blazor support. Include _blazor.js to enable Blazor components. (As described in the tutorial) Click on the menu item and observe the double execution of the action in the browser's network tab.

Git Repo: https://github.com/KevinMartins84/BugReportMVCWithBlazor

Exceptions (if any)

No response

.NET Version

dotnet --version

Anything else?

.NET SDK: Version: 8.0.403 Commit: c64aa40a71 Workload version: 8.0.400-manifests.e99c892e MSBuild version: 17.11.9+a69bbaaf5

Runtime Environment: OS Name: Windows OS Version: 10.0.22631 OS Platform: Windows RID: win-x64 Base Path: C:\Program Files\dotnet\sdk\8.0.403\

.NET workloads installed: Configured to use loose manifests when installing new manifests. [android] Installation Source: VS 17.11.35327.3 Manifest Version: 34.0.113/8.0.100 Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.android\34.0.113\WorkloadManifest.json Install Type: FileBased

[maccatalyst] Installation Source: VS 17.11.35327.3 Manifest Version: 18.0.8303/8.0.100 Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.maccatalyst\18.0.8303\WorkloadManifest.json Install Type: FileBased

[ios] Installation Source: VS 17.11.35327.3 Manifest Version: 18.0.8303/8.0.100 Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.ios\18.0.8303\WorkloadManifest.json Install Type: FileBased

[aspire] Installation Source: VS 17.11.35327.3 Manifest Version: 8.1.0/8.0.100 Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.aspire\8.1.0\WorkloadManifest.json Install Type: FileBased

[maui-windows] Installation Source: VS 17.11.35327.3 Manifest Version: 8.0.82/8.0.100 Manifest Path: C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.maui\8.0.82\WorkloadManifest.json Install Type: FileBased

Host: Version: 8.0.10 Architecture: x64 Commit: 81cabf2857

.NET SDKs installed: 8.0.403 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 6.0.35 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 8.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found: x86 [C:\Program Files (x86)\dotnet] registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables: Not set

global.json file: Not found

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