GPS issues with Lightning 30-pin & Pioneer adaptor

I've been using an iPhone5 since October with Waze (not so much for navigation but commuting traffic alerts) and after a few months purchased the Lightning 30Pin adaptor so I could keep the phone charged via my Pioneer (AVIC-X930BT with a CD-IU51V cord). A short time later I started noticing I would lose the GPS for anywhere from a few seconds to the entire drive (30-40+ minutes).

I did a re-install of the OS and it still did the same so took it into the Genius Bar and they said it was an issue with the phone's antenna and replaced the phone. The replacement does the same thing. I then noticed it always loses the signal when you first plug it in. Then is on/off while it stays plugged in. If unplugged, it has a GPS signal 100% of the time.

I would really like the A/V & App full function of my iphone+pioneer back, but at the least would like to know how to be able to dependably use GPS and have it charging in the car at the same time.

Are there other Pioneer GPS users that have noticed this with the Lightning adaptor?