I got scared, of course. So I turned to Twitter to check if other affiliates were also experiencing the same thing. At least four people said they also got the same report. One even pointed me to a forum discussion, and from that, I found that a similar thing happened last year.
I did manage to get in touch with Support and the person who I chatted with said they know of this matter and they're doing something about it. (Check screenshot below.) Still, half of me was relieved. Although we already knew that it was a glitch, I couldn't stop worrying. To me, I have to see an accurate result.
When I woke up this morning, I checked my report and it still hasn't changed. But a few minutes ago, my earnings started to "correct" themselves. It's already fixed, and I'm happy.