Are you using the specialised class?

Yes, here is my class:

    public class CRSearchPage : SearchPage
    {
        string parentEntityName;
        public CRSearchPage(string entityName, string parentEntityName, string CRType)
            : base(entityName + CRType + "SearchBox", entityName + CRType + "Grid")
        {
            this.parentEntityName = parentEntityName;
            SetContext("find");
            SavedSearch = true;
            AddTopContent(GetCustomEntityTopFrame("find"));
        }
        public override void BuildContents()
        {
            string licenseMsg;
            if (!LicenseManager.LicenseManager.CheckLicenseKey(AppFactory.ModuleName, this, Dispatch.InstallName, out licenseMsg)) AddError("Erreur de licence:<br/>" + licenseMsg);
            else try
            {
                if (!CurrentUser.HasRights(Sage.PermissionType.View, parentEntityName)) AddError(Metadata.GetTranslation("Errors", "ErrCaseSecurity"));
                else base.BuildContents();
            }
            catch (Exception ex)
            {
                if (ex.InnerException != null) this.AddError(ex.InnerException.Message);
                else this.AddError(ex.Message);
            }
        }
    }

Hello,

Have you seen my previous answer?

Have you got an explanation?

Thanks,

I had not seen that.  But if this is a consistent error with search by date fields then this should be reported as a bug.