It may or may not be a browser problem. Go to about:config and type ‘cache’ in the search window and make sure all caching options are enabled. Some web pages have caching disabled through an instruction in the Http header. Check the html source to see if you see a “pragma= no cache” or something like that.
Tkink I found it.
browser.cache.disk_cache_ssl
Change it to true? It’s currently false.