RT-AC68U Dropping WAN Connection

[Maneck Bodhanwaka]

I recently purchased an Asus RT-AC68U after reading numerous good reviews about it but it's been nothing but problems for me.

I'm running Merlin's 378.51 and have been facing problems with the WAN disconnecting. The router is connected to an ethernet socket in the wall and dials in via PPPoE. The router stays on and the device stays connected, it just drops the WAN connection. I can reconnect it by replugging the WAN cable or restarting the router. But doing this thrice a day is not ideal.

I've attached the log. It seems that the router disconnects at this point but I might be wrong:

Mar 11 20:35:37 kernel: br0: received packet on eth1 with own address as source address
Mar 12 00:36:02 syslogd started: BusyBox v1.17.4
Mar 12 00:36:02 RT-AC68U: start httpd
Mar 12 00:36:02 kernel: klogd started: BusyBox v1.17.4 (2015-02-23 18:03:35 CST)
Mar 12 00:36:02 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_eth0)!
Mar 11 20:37:27 pppd[875]: Serial link appears to be disconnected.
Mar 11 20:37:30 WAN Connection: Fail to connect with some issues.
Mar 11 20:37:30 stop_nat_rules: apply the redirect_rules!
Mar 11 20:37:33 pppd[875]: Connection terminated.
Mar 11 20:37:33 pppd[875]: Modem hangup
Mar 11 20:38:18 pppd[875]: Timeout waiting for PADO packets
Mar 11 20:39:33 pppd[875]: Timeout waiting for PADO packets
Mar 11 20:40:48 pppd[875]: Timeout waiting for PADO packets
Mar 11 20:42:03 pppd[875]: Timeout waiting for PADO packets
Mar 11 20:43:18 pppd[875]: Timeout waiting for PADO packets

Has anybody faced similar issues? Is the router faulty and do I need to send it back? I've been trying to fix this for 3 weeks now with no luck.