I've never experienced that until yesterday. Normally when I get an event popup and click the button to view it PC will show the correct updated balance.
Actually, I think you're describing a different issue because I went back in the PC app and the games many times over quite a number of hours and it didn't update the total.
I think it was a system issue because there were many people posting about it on the PC FB page, and there weren't any before that. I view the PC FB page everyday.
10 minutes... that's very fast. Good find.