I have a Samsung Captivate Glide running android 4.2.2 (an unofficial version of Vanilla RootBox with a kernel called Litekernel). This phone is originally for AT&T but it's unlocked and I'm using it on Mexico's carrier Telcel (and I've seen multiple people with the same issue on different countries/carriers).
My issue is that sometimes when someone calls me, the phone rings on their side as if I wasn't picking up and eventually goes to voicemail, but I get no call at all, it's not a sound/vibration setting, I've checked. Also I've read about this kind of issues with multiple phones/carriers.
Once I tested this with another phone and called mine and the call didn't come until I pressed the power button to unlock the screen, waking the phone.
Also I read about some guys using an app called Wake Lock - PowerManager and using the option PARTIAL_WAKE_LOCK to keep the phone from going to deep sleep, but of course that consumes the battery much faster.
Does anybody have any idea what could be done?
My phone is rooted and I'm willing to modify the kernel or do any complex action required to fix this...
Edit: I forgot to mention I have reflashed this rom several times, every time clearing the cache, dalvik chache, factory reset, etc. And this happened to me in other roms as well...