RBK53S - Wifi Thermostat Intermittently Drops Connection

[MASTERNC]

I installed an RBK53 system earlier this year to replace a Fios router with network extender (where there were issues transitioning from one to the other in the house).  I also have an American Standard wifi thermostat that worked well with the old system.  However, the system now seems to randomly lose the connection to the network.  If I go to reconnect it (during which I have to re-enter the network password), it is unable to reconnect.  I then have to reboot the entire HVAC system (which reboots the thermostat).

Again, I don't think it's the thermostat since it worked with my old network system (the thermostat is only 3 years old).  Any suggestions to fix this?

[FURRYe38]

What Firmware is currently loaded?
What is the Mfr and model# of the ISP modem the NG router is connected too?

What is the size of your home? Sq Ft?
What is the distance between the router and satellite(s)? 30 feet is recommended in between them to begin with depending upon building materials when wirelessly connected.

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and any unused channel on 5Ghz.
Any Wifi Neighbors near by? If so, how many?

Try enabling Beamforming and MIMO(MIMO may or maynot be needed) and WMM. Under Advanced Tab/Advanced Settings/Wireless Settings

Try disabling the following and see:
Daisy Chain, Fast Roaming, IPv6 and Set 20/40Mhz Coexistence to 40Mhz only. Save settings and reboot the router and satellite(s).