After upgrade to OSA 7.0.0 monthly invoices started to be generated for the subscriptions that are expected to be billed once in a year (Yearly Charge Before Billing Period subscriptions, e.g. domains).
Issue is caused by the bug with id #PBA-77602 ("monthly invoices instead of yearly").
The bug is fixed in the hotfix for 7.0.0 - #PBA-78070, kb #130053
hotfix for 7.0.1 - kb #130102.
Install the hotfix applicable to the product version currently installed.