I didn't have many drops using the PTV3000. If that's the one you got make sure it is on the latest firmware. I haven't used it yet with the 4100nex. My experience was that blending worked on the Appradio 2 and with the 4100nex when using Android Auto. I may try some things.
Are you just choosing HDMI on the radio to display the phone or are you using Appradio mode or just going to HDMI input?