On Tuesday we have deployed an update to improve serving ratios that were off for some apps. Unfortunately a bug was introduced in the process which resulted in exchange ads for some apps being substantially underserved and substantially overserved for others. The bug is now fixed and the stats should normalize over the next 2 days. I am terribly sorry for the inconvenience this could have caused you.
When things settle down we will compensate the deficit for those underserved and if you got more than you had to get… well, consider this as your lucky day 😉