INPC003 warns incorrectly about calculated property when ++

[JohanLarsson]

    public sealed class SymbolLoadStatus : INotifyPropertyChanged
    {
        private static readonly int TotalCount = Database.GetAllSymbolKeys().Count();

        private string? displayText;
        private int processed;
        private DateTimeOffset? startTime;
        private DateTimeOffset? endTime;

        public event PropertyChangedEventHandler? PropertyChanged;

        public int Total => TotalCount;

        public TimeSpan? Elapsed => (this.EndTime ?? DateTimeOffset.Now) - this.startTime;

        public TimeSpan? Average => this.Elapsed / this.Processed;

        public string? DisplayText
        {
            get => this.displayText;
            private set
            {
                if (value == this.displayText)
                {
                    return;
                }

                this.displayText = value;
                this.OnPropertyChanged();
            }
        }

        public int Processed
        {
            get => this.processed;
            private set
            {
                if (value == this.processed)
                {
                    return;
                }

                this.processed = value;
                this.OnPropertyChanged();
                this.OnPropertyChanged(nameof(this.Average));
            }
        }

        public DateTimeOffset? StartTime
        {
            get => this.startTime;
            private set
            {
                if (value == this.startTime)
                {
                    return;
                }

                this.startTime = value;
                this.OnPropertyChanged();
                this.OnPropertyChanged(nameof(this.Elapsed));
                this.OnPropertyChanged(nameof(this.Average));
            }
        }

        public DateTimeOffset? EndTime
        {
            get => this.endTime;
            private set
            {
                if (value == this.endTime)
                {
                    return;
                }

                this.endTime = value;
                this.OnPropertyChanged();
                this.OnPropertyChanged(nameof(this.Elapsed));
                this.OnPropertyChanged(nameof(this.Average));
            }
        }

        public void Load(SymbolKey key)
        {
            if (this.startTime is null)
            {
                this.StartTime = DateTimeOffset.Now;
            }

            this.Processed++;
            this.DisplayText = $"Loading {this.processed} of {this.Total} in {this.Elapsed:mm\\:ss} average {this.Average?.TotalMilliseconds:F0} ms {key}";
        }

        private void OnPropertyChanged([CallerMemberName] string? propertyName = null)
        {
            this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }