I noticed the exact same thing and just thought I was screwing up the save somehow. I'm running the SuperDark DJ05 ROM with JT's 12/30 kernel and I could not get the settings to save. It worked fine when I was on the DI01 SuperClean ROM.
I find it unacceptable that this is even necessary and now that I've done the OTA update I'm VERY ticked off that I now (again) have useless navigation.
I've seriously had it with the issues with this phone. I really want to love it but things don't work as they should. Seriously...navigation volume so low you can't use it in a car, and Samsung hasn't even acknowledged it as an issue, let alone tried to fix it.
Thanks Jercules. It worked when I flashed the kernel back to StupidFast 1.23 (DI01), changed the system settings, then flased the kernel back to JT's 12/30 kernel (DJ05). What's the reason that this works with the DI01 kernels and not the DJ05 kernels? Will I have to do this all over again if I update to the new DL09 package that Adrynalyne put out?