DataTime issue while importing data from datamigration tool in CRM

Hi,

I have created crm data with the help of DataMigration tool in crm and trying to import it in different server with same time zone(UK and dd/MM/yyyy).

Now issue is occurring with datetime field if date is 31/12/2018, tool storing it as null in CRM but if data is 12/12/2018(where day is within the range of month) it storing in CRM.

CRM system setting for datetime format and Logged in User option setting for datetime format is identical to target server's CRM.