modulepreload links show href="[object Object]" with loadComponent during SSR/CSR transition

[askeric]

Which @angular/* package(s) are the source of the bug?

router

Is this a regression?

Unknown

Description

Repro:
Put this in your route in an SSR/CSR app (note the loadComponent),

  {
    path: 'ssr-test',
    loadComponent: () =>
       import('src/app/ssr-test/ssr-test').then(
        (c) => c.SsrTestComponent
      ),
    resolve: { diveSites: divesiteResolver }, 
    data: { prerender: false }
  },

In ServerRoute, put this

  {
    path: 'ssr-test',
    renderMode: RenderMode.Server  
  },

Go visit the route and you'll see an error downloading resource "[object Object]" as the page transitions from SSR to CSR.

You can see this at the bottom of the page when doing a view source:
<link rel="modulepreload" href="[object Object]">

If I switch from loadComponent to component in my route, the issue goes away

{
    path: 'ssr-test',
    component: SsrTestComponent,
    resolve: { diveSites: divesiteResolver },
    data: { prerender: false }
  },

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 20.0.2
Node: 22.14.0
Package Manager: npm 10.9.2
OS: win32 x64

Angular: 20.0.3
... animations, cdk, common, compiler, compiler-cli, core, forms
... google-maps, material, platform-browser
... platform-browser-dynamic, platform-server, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.2000.2
@angular-devkit/build-angular   20.0.2
@angular-devkit/core            20.0.2
@angular-devkit/schematics      20.0.2
@angular/cli                    20.0.2
@angular/fire                   20.0.1
@angular/ssr                    20.0.4
@schematics/angular             20.0.2
rxjs                            7.8.2
typescript                      5.8.3
zone.js                         0.15.0

Anything else?

No response

[alan-agius4]

Please update the @angular-devkit/build-angular to the latest patch version.