Yes, it is odd.
No problems with fmcarkit so far, but never used it longer than one/two hour or phone calls longer 30 minutes.

But my phone sometimes behave as you described without fmcarkit enabled!
How long is the uptime of your device. when this happens? More than one/two days? I have not found any solution to that else than a reboot.
Or does it happen also after fresh reboot?