EX8000 - stability issues

My router is the ASUS GT-AC5300, which is working great on stock firmware. Meanwhile,with 2 spare repeaters, i decided to deploy my ex8000 on the latest firmware, to the 2nd last room in the house. setup was normal though, however within minutes the unit was quite unstable. I then disabled the 2.4ghz and use only the both 5ghz. 

1. 2.4ghz was disconnecting dropping earlier and then while using both 5ghz, the connection was pretty unstable,

2. The unit was blinking red though the distance was not that far from the router

3. the issues remained despite i setup twice again, even via WPS

4. ex8000 ip address take ages to load

Such issues was not even present while i was using the Netgear Orbi RBR50, the EX8000 Sync VERY well with the router, very stable. Well, gotta bite the bullet since RBR50 was sold off.

Now using the ASUS RP-AC68U Repeater......works beautifully with mine ASUS GT-AC5300, my own conclusion - simply compatibility issue. Seem the EX8000 may not work with any other router per se. However, i would still be keeping the EX8000 for future usage if i were to switch back to Netgear again.....well i would.

I include my email for personal further chat on netgear issues - kungfu1974@gmail.com