The CE device could be connected to the PE devices through an aggregated (port-channel) link, rather than through a regular Ethernet link.
In such a case, the port-channel interface on a PE device must be associated with the down MEP, which when detects the port-channel link down event. That event triggers a fault indication to be propagated to the peer RMEP, which will then bring down the port-channel interface associated with it on the remote side.
Also, the international link or the WAN between the connected NE devices could been deployed with port-channel links. In this case, it is expected that this port-channel link carries the ETH-CSF information towards the remote side as does a regular Ethernet link.