Default GSM flashed 4.4 and now dropping calls.

As the title says, i flashed Slimkat 4.4 onto my old GNex that my girlfriend is using and within a couple days she told me that almost every call is getting dropped within 30 seconds to 5 minutes. The one time i saw it happened i saw no signal drop but the call went silent and eventually ends if she does not end it first.

I asked in the slimkat topic but no one has reported similar issues and i've done a lot of google searches and haven't had much luck on anyone with a similar issue. I'm assuming that it might just need a new radio but i'm not sure if there is one or where to find it.

So I'm looking for any help or ideas as to how to go about fixing this. I'd like to leave her on kitkat as it does make the phone run better but if necessary I'll go back to stock.