Ghost calls are indeed a part of V20p (and all gingerbread updates for this phone as far as I can tell). Nothing to do with root. There's no way to know its happening unless the person who tried to call you chews your ear off later on about not answering your phone or calling back (my wife). Or when you recieve the voicemail to the call you never got.
Now if only the ghost calls would limit themselves to telemarketers...sigh
Seriously though, if the person calling doesn't make it known they tried to call you then you'll likely never know it even happened. This is something they need to fix ASAP and I would suggest flooding their emails and forums demanding a fix. I know I am.
Sent from my LG-P925 using XDA App
HTC Aria --CM7-- retired as mp3 player
Samsung Captivate --CM7-- to the wifey
LG Thrill 4G --ThrillSeeker 2.2 -- Retired
Samsung Galaxy SII --CM9-- Current