Why do I receive the errors and sometimes receive multiple records on inserts through the Data Import Wizard?

Environment: 

Oracle B2C Service Console

Issue:

We sometimes receive the error "There is an unclosed literal string" or "Unable to communicate with server" and sometimes receive multiple records on inserts through the Data Import Wizard?

Resolution:

If you see errors similar to these in the Error Log:

pair <c_id> is not visible looking for <FV_U> visibility...
Deadlock found when trying to get lock; try restarting transaction

...and are seeing multiple records being created during the data import process, this could be due to one of the following reasons:
 

1. Data import processing limit too high. 
   
   To resolve this, set the DATA_IMPORT_BATCH_LIMIT configuration to a lower limit, for example 250.
   
   A description of this configuration is as follows:
   
   DATA_IMPORT_BATCH_LIMIT
   Limits the number of contacts processed in a single batch when performing a Data Import. Maximum is 5000. Default is 1000.

   Please note that this is an interface specific configuration, and you can find it using the path: Configuration > Site Configuration > Configuration Settings > search by Key.
    

2. Rules are not being suppressed. 
   
   If you are using a Custom Process Model (CPM) in the process, add Suppress Rules to the "save", as described here:  Create/Update Options.
    
3. If you are using a CPM within the business rule, consider moving it to within an Event Handler, as there is a possibility of a loop that is creating multiple records.