Symptoms
In Home>External Systems Director>Domain Manager>Domains in PBA-E 5.4 and earlier or Home>Services>Domains in PBA-E 5.5 and later there are several duplicate domains in Prepared status.
Cause
Sales order for those domain failed and were cancelled. But domain status is not changed when sales order is canceled.
Resolution
Nothing should be done. PBA-E will allow to place new order for domain if it already exists in Prepared status.
Feature request #PBA-27925 was created, so that domains are moved to Canceled status when order for them is canceled.