Default G2 D802 KK and bluetooth problem

I have a big problem with my LG G2 D802 with KK Rom 20D - "Open Germany".

The problem is that it is impossibile for me to connect my phone to my external bluetooth GPS antenna.

Everytime I tried, this is what happens:

Before you asking:

- it isn't a problem related to the kernel ( I have the Dorinmax Kernal 5.0) because I tried also with stock kernel and the problem is the same.

- it isn't also a problem of the app. It is a problem of the version of KK for LG G2. Anyway as last chance I tried with 20B and the problem remains.

I had JB and wth it everything was perfect. Now I don't think so it is a problem of my bluetooth GPS antenna because with the Nexus 5 I am able to connect the phone to the external antenna.

So the problem as I said before is related to the KK version of D802.

Does anyone else have this problem ?

Thanks !