A supposed bug in the App Store ranking algorithms pushed paid apps to the summit of the typically free-to-play dominated top grossing charts.
As noted by TechCrunch, the problem appeared to surface on Friday, February 17th. It affected top grossing charts across every category but did not affect either of the top download charts.
For example, on the UK App Store an app to help people taking their driving theory test shot up to #2 on the top hrossing chart.
Curioser and curioser
The problem worsened over the weekend, with more niche apps joining the ranks. Games such as Construction Manager Pro started appearing in the upper rankings alongside paid camera and translator apps.
Theories began to spread that this might be a deliberate change on Apple's behalf. However, the bug was eventually fixed on Monday, February 20th at around midnight.
One theory suggests that Apple deliberately changed the algorithm to give new apps a chance at entering the top of charts. These charts are regularly topped by titles like Candy Crush Saga and Clash of Clans with little to no change for months at a time.