Why does Resharper think my class members are "non nullable"?

In my .C#/.NET Core 3.1 App, Resharper complains about the fact that my class is failing to initialize one of its properties because, it says, "Non-nullable class properties are not initialized on all paths".  Then it names the properties.  They are all public properties with public getters and private setters that are definitely nullable.  They are designed to be nullable, depending on which constructor the user uses.  Sometimes they can be initialized later one.

I have not marked these properties it with any attributes to indicate otherwise
So can anyone tell me why is CA might think this thing is non-nullable?

Here is the code to illustrate.  Note the properites "FlatField" and "Model".  The first constructor complains that I failed to initialize both of them.  The second complains that I failed to initialize "Model"

    public class CalibrationJob : JobVm
    {
        private readonly ICaptureService            _capture;
        private          List<ITargetContextJob>    ScanJobs        { get; }
        private          List<IParameter>           Parameters      { get; }
        private readonly string                     _calibrationName;
        private readonly string                     _fileNameBase;

        public           ICalibrationModel          Model           { get; private set; }
        public           IDevice                    Device          { get; } // Camera used to capture the scans.

        public CalibrationJob(
            IDevice                        device,
            ILogger                        logger,
            ICaptureService                capture,
            IEnumerable<ITargetContextJob> scanJobs)
            : base(logger, Strings.Calibrate)
        {
            _capture        = capture;
            Device          = device ?? throw new ArgumentException(Strings.NoDevice);
            ScanJobs        = scanJobs.ToList();

        }

        public CalibrationJob(
            IDevice                         device,
            ILogger                         logger,
            ICaptureService                 capture,
            IEnumerable<ITargetContextJob>  scanJobs,
            IEnumerable<IParameter>         parameters,
            FlatField                       flatField)
            : base(logger, Strings.Tune)
        {
            _capture            = capture;
            FlatField           = flatField;
            Device              = device ?? throw new ArgumentException(Strings.NoDevice);
            ScanJobs            = scanJobs.ToList();
            Parameters          = parameters?.ToList() ?? throw new ArgumentNullException(nameof(parameters));
        }