The fast mode status check now caches results for 30 seconds to reduce redundant API calls. When you rapidly toggle fast mode or navigate between sessions, the CLI will reuse recent status checks rather than querying the server each time.
Evidence
Prefetch debouncing with 30-second interval (search for "Skipping penguin mode prefetch, fetched recently")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.