Nullables introduced in 3.1.0 not allowed, but default behaviour should be to ignore nullable than destroy field

[Tanakpek]

Openapi spec:

"dates": {
                    "anyOf": [
                        {
                            "items": {
                                "type": "string"
                            },
                            "type": "array"
                        },
                        {
                            "type": "null"
                        }
                    ]
              },

creates.

public partial class Dates
    {

    }