Can't get a container to use a custom port

[codekoenig]

I need one service/container of my Aspire app to use a custom port (5050) instead of 8080.

I did this in the AppHost:

var builder = DistributedApplication.CreateBuilder(args);

var secondapi = builder.AddProject<Projects.SecondApi>("secondapi")
    .WithEndpoint("http", endpoint =>
    {
        endpoint.Port = 5050;
        endpoint.IsProxied = false;
    });

builder.AddProject<Projects.OtelSampleApi>("otelsampleapi")
    .WithReference(secondapi);

builder.Build().Run();

And the generated manifest after running Aspire looks like this:

  "$schema": "https://json.schemastore.org/aspire-8.0.json",
  "resources": {
    "secondapi": {
      "type": "project.v0",
      "path": "../SecondApi/SecondApi.csproj",
      "env": {
        "OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EXCEPTION_LOG_ATTRIBUTES": "true",
        "OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EVENT_LOG_ATTRIBUTES": "true",
        "OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY": "in_memory",
        "ASPNETCORE_FORWARDEDHEADERS_ENABLED": "true",
        "HTTP_PORTS": "{secondapi.bindings.http.targetPort}"
      },
      "bindings": {
        "http": {
          "scheme": "http",
          "protocol": "tcp",
          "transport": "http",
          "port": 5050
        },
        "https": {
          "scheme": "https",
          "protocol": "tcp",
          "transport": "http"
        }
      }
    },

But the built container still uses 8080.

Is there something I need to do differently to get the container to use 5050?

I'm building for Compose btw.

Thanks!