Hey arpitch,
I fixed the issue myself, hereunder you can read how I did it.
All customers and the Access Concentrators are part of the same EVPN instance.
When a random customer wishes to obtain an IP address with PPPoE, a PADI packet is sent towards the EVPN instance.
Then all devices, including other customers connected to the EVPN instance, get to learn the MAC address from that customer (since it is a broadcast packet).
A family bridge output filter towards the customer fixes this issue. The filter discards all PADI broadcast packets towards CPE's while allowing all other discovery and session packets (communication between AC and CPE).
The input filter accepts all discovery and session ether-type packets.
Beeelze