The same exact thing happens on my 4100 NEX when using Android Auto. Phone (Moto Z) gets really hot, voice recognition goes to crap and AA glitches and lags. Im pretty sure the issue is the phone thermally throttling though, not the NEX, because the rest of the sources (iPod, HD Radio, etc) function perfectly fine and the phone still misbehaves after disconnecting from the radio. I think the combination of the battery charging, GPS, and ambient temperature in the summer cause the phone to overheat and lag. Best bet is to keep the phone out of the sun and/or in front of a vent with the A/C