Using Deco M9+ in Static Ip mode and modem in bridge mode breaks connection frequently. 

I recently bought a new Deco M9 Plus set of 3.

Initially I set it up with the deco in dynamic ip mode and modem in router mode. 

As everything was working great but I was having double NAT issues so I decided to run the M9 Plus in Static IP and my modem in bridge mode. 

Since then I have been having constant network breaks on both WiFi and Ethernet which they resolve themselves on reboot or roughly after 10 mins but reappear after half an hour or so. 

When I try to ping my router or google via terminal on my computer the "request timed out" comes after every 7 pings or so. Which doesn't come when I configure the Static IP in my computer and put the modem in Bridge mode.

Reverting back my setup to the original setup with decos in dynamic ip mode works perfectly fine. 

Kindly help me resolve this issue so I can run my deco in Static IP and modem in bridge mode. 

Ps:- I don't wanna use AP mode on my deco.