I understand it happens on one of the Reddit apps as well.
I'm just saying that it seems like sloppy QA if they don't test the phone against one of the most popular benchmarking apps on the Play Store. OnePlus try to cater to enthusiasts so I am quite astonished they didn't see this, to be honest. That's what I meant by sloppy.
Well hopefully it's just a software problem. I myself bought the 8gb version and don't have any problems at 60hz or 90hz running the latest oxygenOS and latest cpu-z app.
From what I've seen of the problem it's definitely inconvenient to put it lightly. I wouldn't be happy if mine was doing it.