Db.SaveChanges() not saving correctly at release mode - entity-framework

Question

I'm trying to save a checkbox to db. It works right at debug mode but switching to release or custom release without code optimizations as explained here doesn't. Db is Sqlite. Looking with DB Browser for SQLite SimpleCheck field is just NULL or 0 at release and NULL, 0 or 1 at debug. (Edited)
private void SetSingleCheck(CheckBox box)
{
var processId = (int)box.Tag;
using (var db = new AgendaContext())
{
var check = db.Checks.SingleOrDefault(c => (c.ProcessId == processId) && (c.Date.Date == SelectedDate.Date.Date));
if (null == check)
{
check = new Check()
{
ProcessId = processId,
Date = SelectedDate.Date
};
db.Checks.Add(check);
}
if (box.IsChecked.HasValue)
{
check.SimpleCheck = box.IsChecked.Value;
}
db.SaveChanges();
}
}
Relevant parts of the model, just in case:
public class Check //Check if this process is ok or not, TODAY
{
public int CheckId { get; set; }
public DateTimeOffset Date { get; set; }
public Process Process { get; set; }
public int ProcessId { get; set; }
public bool? SimpleCheck { get; set; } //USed for checked situations. example: clean this thing: Ok, i have cleaned it.
public bool? DoubleCheck { get; set; } //Used for ok/no ok after doing something.
public ObservableCollection<Temperature>Temperatures { get; set; }
}
public DbSet<Check>Checks { get; set; }
What is wrong or missing? Thank you.

Answer 1

Error source was in the model
public bool? SimpleCheck { get; set; }
As there are no booleans in sqlite it seems that the ef core converter fails somewhere if its nullable, it assigns null if false and 0 if true, while expected results are 0 and 1. Reproduced in a test solution. Just making it non-nullable and adjusting null-checks at code did the trick.