Caching on the web has gotten worse/more difficult recently since browsers (including Chrome and Edge) have started to partition the cache by top level site. This was necessary to keep trackers from using the cache status of a resource for tracking users, but had the side effect of making common resources much less likely to be cached.
Which is to say that if it's the first time you load a resource on a page, it most likely is not in cache. Sorry for inconvenience.