The DB3-journal file is a SQlite file that is similar to a transaction log for SQL. This file does not always exist( as it is usually temporary) and it is created for rollback capabilities upon insertion of data to the DB.With that being the case we need to check for it before writing to the DB.
I think you can delete the .db3 file and recreate it. For detail you may refer to below Community document:
Thanks Leon - I downloaded sqllitebrowser and all looks fine, I'll stop worrying about it.