surprise surprise: it took them 3 months to figure it out (the average accountant needs 3 days) but they "overpaid" us and will take it back:
Rather than take this amount out of your royalty balance in one adjustment we have decided to schedule the removal of these funds over a 6 month period.
Looks like we are not getting much the coming months. Still no proper explanation how this could have happened and I miss one phrase in this email: we are sorry!!
If you have any questions please contact us via our Contributor Relations Contact Ticket feature. Thinking of sending them a message about my underpayment: 15% sucks!