For me it's working fine (I have even a 3 mash version). Have you tried to set it up next to the main router and then only move the satellite to the location where it should be?

I had the same problem, but to solve it, you need to:
1. Update the firmware

2. Place the devices at a distance of 1m. and restart the pairing process via the Asus application

3. Let the devices go through the optimization process and reboot

4. If the problem starts again, simply switch off the device and restart it

I have had 2 devices for over a year, in 2 different floors and I have only had the coupling problem once.

Got similar issue. I agree it is not working as expected