Bluetooth for Android Lollipop

Just wondering if anyone has had this problem and if so if there's a solution. I have a 2006 Prius and a LG Optimus Pro E980 phone. Running the version of Android that came on the phone (4.1.2 - rooted) I have no problems making or receiving calls with the bluetooth. This includes using the car to initiate the call. However, as my version of Android is getting older I was looking at flashing a newer version of Android on my phone - some apps on the Play store are starting to report that they won't work with my version of Android. So I flashed
a Cyanogenmod 12 or 12.1 version on my phone, and while it works [somewhat] with the bluetooth, there's
an issue that keep me from using it. I can pair the phone to my car, and usually, the first call I initiate from my car will work, but then when I try a 2nd call, it will start to dial and the phone screen changes, but then the
car screen will come up before the call completes saying that the call was terminated by network, or similar
verbiage - and I've had this happen both when the car originates the call or when the phone does. Since it ALMOST works (1st call works fine), it appears there's a timing issue when the call is placed where the car or the phone aren't waiting long enough to see that things are working before one end or the other terminates the call. Anyone else had a similar problem and found a solution? Wondering if Toyota has a bluetooth firmware for a 2006 Prius that might solve the problem? If not I guess I'll stick to my old Android 4.1.2 till it gets too old to add any more apps to. I've tried deleting my phone and re-pairing my phone to my car, and clearing the data in the bluetooth sharing app, but nothing I try fixes it. Any thoughts appreciated.