The Unearned Revenue account is only used in Cash accounting as a "pass-through" account for payments received. When a payment is entered in PropertyBoss and added to a deposit, the funds are credited to the Unearned Revenue account. When the payment is applied to a charge in PropertyBoss, a journal entry is sent to QuickBooks as a debit to Unearned Revenue and a credit to the Income account for which the charge is mapped to.
In PropertyBoss, the Unearned Revenue account is increased by the amount of any prepayments. When the prepayments are applied to charges, Unearned Revenue is decreased.
The A510 report will show the total amount of prepaid tenant credits, and this should balance to Unearned Revenue in QuickBooks.