They just made another post here - Update on Questions around Estimated Earnings for April Payout
It’s some sort of bug and they say it’s fixed / will be fixed for next month. Our browsers have been failing to validate ad payments and this has not been handled correctly in software. Once they fix it, the browser should retry and revalidate the missing payments and we should get our payments in May.
Thanks @steeven for looking into this and helping it get to the right people.