Three cache bugs broke a dashboard's badges — and how each was fixed

A development team building a cross-site updates dashboard implemented a cache-first design, but quickly encountered three separate bugs that all produced the same user-facing symptom: badges not persisting as expected. The first issue was that cache restoration only triggered when the dashboard was opened, meaning a site-list badge rendered at boot saw an empty cache and hid all badges; the fix was moving restoration to DOMContentLoaded so it runs once at app startup. The second problem was a 7-day cache TTL based on an assumed usage pattern that did not match reality, where users checked the dashboard infrequently and relied on badges between visits; the team extended the TTL to 30 days and added a tooltip showing how old the cached data was. A third bug caused maintenance on a single site to invalidate the entire cache, wiping badges for all other sites. Each fix highlighted a broader principle: cache restoration logic should be tied to app boot rather than the first consumer that happens to use it, and longer TTLs should be paired with visible data-age indicators rather than shorter expiry windows.