Different DateTimeOffset deserialization on Mac and Linux

[gbreen12]

I'm running a .Net 5 Web API and I'm seeing different values when deserializing date time offsets.

Source/destination JSON

{
    "Date": "03/09/2021"
}

Expected behavior

Deserialize with local offset (or ability to specify via settings)

Actual behavior

On Mac, it is deserializing to my local offset but on linux (via Docker) it is deserializing with a 0 offset.

Steps to reproduce

Here is my docker file:

FROM mcr.microsoft.com/dotnet/sdk:5.0-buster-slim AS build
WORKDIR /app

COPY . .
RUN dotnet restore Cuwcd.WebApi.sln
RUN dotnet publish Cuwcd.WebApi.sln -c Release -o out

FROM mcr.microsoft.com/dotnet/aspnet:5.0
RUN apt-get update && apt-get install -y libgdiplus
WORKDIR /app
COPY --from=build /app/out ./
ENTRYPOINT ["dotnet", "Cuwcd.WebApi.dll"]

Here is my C# setup:

var mvc = services.AddMvc();//.SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
mvc.AddMvcOptions(options => { options.EnableEndpointRouting = false; });
mvc.AddNewtonsoftJson(options =>
{
    options.SerializerSettings.ContractResolver = new DeltaContractResolver(new JsonMediaTypeFormatter());
    options.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
    options.SerializerSettings.Converters.Add(new StringEnumConverter());
    options.UseMemberCasing();
});

I've tried setting the DateParseHandling and the DateTimeZoneHandling but neither fixed the issue.

[gbreen12]

I created a simple web api project to show the issue:

https://github.com/gbreen12/Json.Net-Deserialization

Run locally on Mac to see the local offset, run in docker to see 0 offset

[gbreen12]

Turns out I have to set the timezone on the docker container. That fixed the issue.