This generally occurs when you have transactions that belong to a previous company and you have processed for a new company.  An example of this would be an unbilled disbursement that was for the old company and you billed it for the new company. Then the system will create these types of entries.

 

From the general ledger, when you are reviewing the transactions, if you select the source, audit or journal tabs, this may show further information as to what it relates to.