Entity Framework writing NULL to the DB - entity-framework

Question

I am using EF v 6.2.0. My issue is similar to the SOF question - Entity Framework not claiming datetime.now is null. However, the proposed solution does not work for me.
buildDetail.BuildTime = epoch.AddMilliseconds(Double.Parse(buildTime)).ToLocalTime();
:
:
: // Other properties.
ps.dbEntities.BuildDetails.Add(buildDetailT);
ps.dbEntities.SaveChanges();
On the SaveChanges() line, I get an exception
Inner Exception 2:
SqlException: Cannot insert the value NULL into column 'BuildTime', table 'BuildDetailsDB.dbo.BuildDetails'; column does not allow nulls. INSERT fails.
The statement has been terminated.
The buildDetail.BuildTime property, when I hover over in debug, shows the value as {3/29/2018 9:17:22 AM} i.e. current date time. The datatype in Sql Server is datetime and the model I have generated from the database shows that this field has a return value of System.DateTime. So, I am frustrated as to why EF is trying to insert a null. In fact, if I allow nulls for this columns in the DB, that is exactly what it writes in that column - NULL.
The field in question is neither marked as Identity (both in model and db) nor Calculated. I have also updated the model from the Database and they are in sync.
Note: I have tried the DateTime.ParseExact and even an DateTime object converted from a string in the exact same format as expected in SQL Server i.e. "yyyy-MM-DD HH:MM:SS.FFF" with no luck and the same exception. eg.
buildDetailT.BuildTime = DateTime.Parse("2018-11-25 08:25:26.0000");