Incorrect comparison of datetime and datetime2

I know that it is not a good practice to have an implicit type convert. But this is really unexpected behavior when a lower value can suddenly become higher. declare @LastSelectedDate DATETIME = '2021-11-09 13:52:29.187' declare @LastSelectedDate_1 DATETIME2(7) = '2021-11-09 13:52:29.1866667' SELECT IIF(@LastSelectedDate_1 > CAST(@LastSelectedDate AS DATETIME2), 1, 0) SELECT IIF(@LastSelectedDate_1 > @LastSelectedDate, 1, 0) Is this a bug or I am missing something? I am using sql server 2016.