Products indexed have Product Performance Metrics such as number of buys or conversion rate % which is calculated for a certain timespan (default: 32 days).

Even though changes to Product Attributes are almost instantaneous (such as availability or pricing changes), Product Performance Metrics require batch updates and are calculated every 24hrs.

This essentially means that if a product starts trending due to a sale, the performance improvement is reflected after 24hrs. However if using Product Attributes to account for the change in the sale status, the listing will update to reflect this.