Default Why was HD voice disabled?

So this isn't really a problem but it's just weird, I flashed cm11 on my T-Mobile note3 but then I went back to stock with Odin but when I called someone I noticed I didn't get the HD voice like I usually did when calling that person, so thought to to turn on the aws wideband that was required for HD voice/VoLTE with pimpmyrom I since it may have been disabled, sure enough it was and I turned it on and HD voice works again but I want to know why it got turned off in the first place is it because I'd previously flashed cm11 or what's the reason?
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