According to reports, apps and games from brands including Google, Starbucks, Disney and Microsoft all saw a significant change in ratings - both positively and negatively - and the tech giant says it resolved the issue within a week.
In a statement this week, Apple said: "During routine maintenance to the App Store, ratings and reviews were temporarily affected by a bug that has since been resolved.
"While no reviews or ratings were ever deleted, the data displayed to users was impacted for a period of time.
"We apologise for the inconvenience this caused. All ratings and reviews have been restored."
It's said that the bug arrived on October 23, with market researcher Appfigures initially spotting the big drop.
The issue apparently affected 155 countries, while the US was hit the hardest, with 10 million ratings disappearing.
Australian followed closely behind, with 2.7 million app ratings missing.