This may be some issue with my system but I think it's worth reporting in case it is a bug:
Since CC autosaves to cache every 60 seconds, I rarely do a manual save to cache, as I really don't stress about losing 60 seconds' worth of production. Very occasionally do I save to file, for example if I am doing some kind of upgrade and am worried about losing the cache file.
However... a few days ago I was forced to reboot the PC, and after rebooting both the live version and the beta version restarted with a new game, and zero cookies. Somehow the cache was not reloaded. I was forced to load from the last "Save to File", which was a couple of weeks ago, meaning I lost that amount of production.
This is the first time this has happened, and I shrugged it off but resolved to save to file more often. However today it happened again. We had an unexpected power cut, and on restarting both my CC games they failed to find the cached configurations, forcing me once again to call up the last "Save to File".
I experimented just now doing a manual save to cache, and it appears to save correctly. This makes me think there may be something wrong with the autosave.
An alternative explanation is that I have somehow changed my settings so that cookies are not saved between browser sessions, but I have not intentionally made such a change.