This is related to https://github.com/dotnet/corefx/issues/31918 and the same repro described there breaks with .NET 3.0 but the reason appears to be different and due to not using `TryAddWithoutValidation` according to [this](https://github.com/dotnet/corefx/issues/31918#issuecomment-543414911). Basic issue is that headers such as `Expires: -1` are not supported while they are still prevalent.