Mine recently started doing that again shortly after I switched hard drives and just copied the rom folder to the new one.
As far as I can tell, rom is not even trying to write to the config file. I made a copy in a temp folder, then deleted the original thinking it would make a new copy, started the game and made changes, logged out and retried, it never made a new copy.
I have most of the settings figured out, as Auros said, Most settings are on= one, off = zero, others are percents (0.00 to 1) others, view distance etc are whole numbers from 1 to ????
Make a copy of the client.config.ini file and experiment!
I'm beginning to think it's something with game forge live, simply because all the setting trouble started shortly after it came out.