The App Store was recently affected by what appears to be a bug in its “Top Grossing” section that placed paid apps over those receiving revenue from subscriptions and in-app purchases. A change in the rankings appeared on Friday and persisted until Monday.
Another possibility is that an updated algorithm was being tested. This could make sense since the current algorithm keeps pretty much the same apps on the “Top Grossing” list all the time.
One developer found their app had temporarily fallen from #2 to #35.
While things were altered, some lesser-known apps were highlighted at the top of the list. It’s unclear how exposure in that part of the store impacts sales.