We have noticed that your routers have unstable mobile connection. This is the reason why RMS periodically indicates that router's went offline.
To begin with, make sure that both LTE antennas are connected to the routers.
If your routers are located in place, where they are obstructed by concrete/metal constructions (which could interfere with mobile signal), you can try using Wired Mobile antennas, which might help your router's to achieve better connection with mobile towers.
If, however, any improvement to mobile signal reception cannot be done, we would recommend to enable "Redundancy protection" on your RMS alerts, which will still allow you to find out when router's went offline, but will not cause repeating spam alerts for same disconnection: