I found an issue with the latest Asus Router Firmware for the RT-AC5300
ASUS RT-AC5300 Firmware version 220.127.116.11.380.3941
Basically Lifx Color 1000 bulbs do not discover correctly (cant connect to bulb, or discover correctly in lifx app) - even existing bulbs that were previously working fine on previous version of router firmware. Setup of new bulbs does not work on this firmware either.
I downgraded to ASUS RT-AC5300 Firmware version 18.104.22.168.380.3341 and things returned to normal and discover correctly.
Not sure of the specifics of why