I am using the TL-R605 router in a multi Wan configuration as shown in the table below. The LTE modem on WAN/LAN2 port is currently disconnected and no more in use. My primary modem is the 5G (WAN Port) while the backup is the 4G (WAN/LAN1 port) and this has been configured through my Omada Controller. Everything works fine. If I disconnect the WAN port using the Omada App on my phone the internet connection switches over to the Backup WAN/LAN1 port and once I reconnect the WAN port the internet connection switches back to it. 

The challenge I have is that if the primary 5G Modem on WAN port is unabled to reach the internet which happens occassionally the R605 router doesn't detect this automatically and switch to the backup connection. I have to manually disconnect the WAN port for it to switch to the backup port which defeats the purpose.

Is anyone else also experiencing this? How do I resolve this problem?