The logic for preloading middleware in the apiFetch library caches preloaded data. As it stands today, all requests to the preloaded endpoint will reference the cache.

The problem is that the cache is never invalidated during a session. When updates are persisted to the WordPress database, the cache doesn't change, and it will continue to reference the stale, preloaded data.

This fix only allows references to cached data for each preloaded endpoint a single time, after which all subsequent requests to preloaded endpoints will skip preloading middleware.