I would definitely close the motor back up and send it in they are rather new on the seen and I am sure they will want to make good on it.
Also I can not say for sure but a few years back I raced MX and found a lot of Carbon build up and parts failures with Belray products I am sure they are a good oil and have improved like everyone else however I have been running Klotz racing oil and am very impressed with the performance and condition of the motor after several flights. I really don't want to step on any toes just my 2 cents