Have you upgraded the router FW recently ? Try resetting and configuring from scratch.

Have you tried to experiment with wireless settings ? For example set Channel and Channel Width to Auto for 5.GHz. If they are already configured as Auto, there maybe too much wireless interference...

@StinTheGreen Like I mentioned, it may be a configuration issue as well. Be sure that in Advanced Settings of PPPoE settings you have: If the issue persists you can experiment with this setting as...

@Fex Check that reference and see if it can help. Remember that TP-Link products support only L2 LACP - static Link Aggregation. So, look at the NAS link-aggregation settings and see if there is such...

That should be possible only by a new FW version release. Many users are expecting that feature implemented in the future.

@StinTheGreen PADx messages are PPPoE Discovery messages, normal as the connection is built up or torn down, you should not see them normally, it is an indication of a connectivity or configuration...