An order of the customer of the reseller failed and was resubmited for provisioning within some period of time. Upon order completion, the records to the Reseller Activity tab were added, but the line for the resource recurring fee has incorrect duration, it starts from the order placement day, not from the day of successful service provisioning. This results in the reseller being overbilled.
The same situation is possible even when order was not failed, has been left in some intermediate status (before provisioning) for some time.
The issue is caused by the bug with id #PBA-63589 ("Reseller may be billed incorrectly if order with additional resources has failed").
The bug fixed in BA 6.0.5, please update to that product version.