C# Entity Model won't correctly save changes to SQL database -

here's brief summary of code - written long time ago , there on 50 properties written way, yet when added new one, both in model , within viewmodel, refuses save changes:

from view have:

@html.editorfor(m => m.phonenumber ) 

from viewmodel have:

public string registration {get;set;} 

from controller have:

public async task<actionresult> savevehicleinfo(vehicleviewmodel vm){      vehicle vehicle = mapper.map<vehicleviewmodel, vehicle>(vm); (automapper library)     var changes = false;     vehicle dbvehicle = await context.vehicles.findasync(vehicle.id)      //a load more properties etc      string phonenumberchange = "";     if (dbvehicle.phonenumber != vehicle.phonenumber)     {         phonenumberchange = " - phone number changed " + vehicle.phonenumber + " " + dbvehicle.phonenumber;         dbvehicle.phonenumber = vehicle.phonenumber;         changes = true;     }      //at end:      _db.vehicles.attach(dbvehicle);     _db.entry(dbvehicle).state = entitystate.modified;     _db.notes.add(note);      try     {         await _db.savechangesasync();     }     catch (exception e) {         var str = "";     }     return #stuff#; } 

i know not best way of doing it, said written long time ago.

on inspecting item dbvehicle in line:

    _db.entry(dbvehicle).state = entitystate.modified; 

it correctly shows dbvehicle.phonenumber being new value. shows this:

        phonenumberchange = " - phone number changed newvalue oldvalue" 

the save statement goes through, sql logs not show phonenumber being included in update statement. other values save correctly, except new 1 i've done. can manually enter in database, savechangesasync method fires without throwing anything, cannot figure out why it's doing this.

have cleaned/rebuilt whole solution. no idea what's going on.

entity framework version 6.

i think perhaps going wrong in entity framework somewhere. after lot of messing around, deleting model , re-adding seemed fix problem.