LBR20 keeps disconnecting from LTE

The answer needed is are you losing LTE connection or is your device losing access to the Internet, and the LTE connections is still connected. 

Try This:

monitor Internet traffic:
1. Launch a web browser from a computer or mobile device that is connected to your Orbi network.
2. Enter orbilogin.com.
A login window opens.
3. Enter the admin user name and password.
The user name is admin. The password is the one that you specified the first time that you logged in. The user name and password are case-sensitive. The BASIC Home page displays.
4. Select ADVANCED > Advanced Setup > Traffic Meter. The Traffic Meter page displays.
5. Select the Enable Traffic Meter check box.
6. From the WAN Interface menu, select the interface to monitor:
• Ethernet. The router monitores the traffic volume that passes through the LAN/WAN1 Ethernet port when that port functions as a WAN port.
• 3G/4G Mobile Connection. The router monitores the traffic volume that passes through the mobile broadband interface.
7. To control the volume of Internet traffic, use either the traffic volume control feature or the connection time control feature:
• Select the Traffic volume control by radio button and then select one of the following options:
- No Limit. No restriction is applied when the traffic limit is reached.
- Download only. The restriction is applied to incoming traffic only.
- Both Directions. The restriction is applied to both incoming and outgoing traffic.
• Select the Connection time control radio button and enter the allowed hours in the Monthly limit field.