Netboot/Netrestore Hang

I have a good build of 10.11.4 net restore. on virtually EVERY machine i boot to it hangs here....

AppleLPC ::notifyPlatformASPM ASPM callback registered

if the computer(s) freeze here its time to start over, but passing this line and it works fine. Oddly if I unplug the Bluetooth board it will SOMETIMES boot.

The three machines tested range in year and spec but are 2011-2012 13" MBP.

Can anyone enlighten me as to what this is?? and better still how to fix it?