Zac Propersi, an Engineering Manager at Sentry, noticed that the alerts pages were rendering slowly and used Discover to investigate the performance issue. He found out that a slow endpoint call was taking seven seconds to complete, which affected load time. The problem was solved by Billy Vong and Dan Fuller, who deferred the slow-loading queries to run shortly after page loads, allowing relevant alert data to load first. This change resulted in a landing page that loads in under 300 ms, demonstrating the effectiveness of Sentry's performance monitoring capabilities.