What I said in the title. Sadly, no error messages in the console. It seems to happen with any class, and it affects all users. Mod version 0.8.1 in Horizons III, forge version 14.23.1.2556, and running this on a server.

Intended, a mechanic was changed recently. You now have to sleep in a bed to regain charges. This was changed due to you being able to craft, break and pickup, the angelic statue. Meaning you would have been able to just keep one on you at all times to regain charges.