Creating a content with squidex client doesnt work

When I try to create a new content using the squidex client in c# .net core I get a BadRequest response indicating that a field doesn’t exist.

As you can see the squidex client uses the lower case of all the fieldnames. But in Squidex the names are written with a capital letter at the beginning. Maybe this is the problem?

My code looks like this

   public Task AddCity(CityCreationCmd cmd)
        var city = new SquidexCityContent
            Name = new Dictionary<string, string> {[cmd.Lang] = cmd.Name},
            Province = new Dictionary<string, string> {[cmd.Lang] = cmd.Province},
            ShortKey = cmd.ShortKey

        return Client.CreateAsync(city);

The Squidex Client library converts everything to CamelCase. There is an attribute [KeepCasing] to disable this behavior.