@sereneplace This is obviously a TP-Link BUG. No issues with a Teltonika RUT-950 router using the same architecture. Anyway you can apply two workarounds: 1) Modify lease time on the modem's DHCP...

@Vit100 Same problem with TL-ER7206. I solved the issue with a workaround. On the DHCP Server (in your case the Cable Modem) you have to adjust the address lease time. I have set 2 minutes, each 60...