Hi, I'm sorry to put everything here in English, my Deutsch is terrible, and I'm sorry to bother you in such a way.
I've got the following setup at home:

Draytek, that works as a dsl modem in a bridge mode and Ubiquity Edgerouter 4 for pppoe initialization and router.

interfaces {
    ethernet eth0 {
        address 192.168.165.100/24
        description WAN
        duplex auto
        mtu 1500
        speed auto
        vif 7 {
            description "Telekom Internet"
            pppoe 0 {
                default-route auto
                firewall {
                    in {
                        name WAN_IN
                    }
                    local {
                        name WAN_LOCAL
                    }
                }
                mtu 1492
                name-server none
                password ****************
                user-id ******@t-online.de
            }
        }
    }

There are no issues with connectivity and getting an IP address on eth0.7 interface, and keep access to the Web UI of the Draytek modem available on https://192.168.165.1, but for some time I was able to notice discards on eth0 interface. I could gather some monitoring statistics with my LibreSNMP setup:I have double checked mss-clamp:

# show firewall options
 mss-clamp {
     interface-type pppoe
     mss 1452
 }

interface statistics:

~$ show interfaces ethernet eth0
eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 18:e8:29:4c:4e:ce brd ff:ff:ff:ff:ff:ff
    inet 192.168.165.100/24 brd 192.168.165.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::1ae8:29ff:fe4c:4ece/64 scope link
       valid_lft forever preferred_lft forever
    Description: WAN

    RX:  bytes    packets     errors    dropped    overrun      mcast
    6611727912766 6092296480          0   12310169          0   12367734
    TX:  bytes    packets     errors    dropped    carrier collisions
    4125255134146 4778176773          0          0          0

we could see dropped counter almost identical to mcast packets
I've checked the tcpdump:
~$ sudo tcpdump -i eth0 -n -vvv ether multicast
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
18:30:02.673078 unknown (10), length 52
    0x0000:  0a00 19a7 0001 1000 0000 0100 0404 0000
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0030:  0000 0000
18:30:03.675005 unknown (10), length 52
    0x0000:  0a00 19a7 0001 1000 0000 0100 0404 0000
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0030:  0000 0000
18:30:04.677617 unknown (10), length 52
    0x0000:  0a00 19a7 0001 1000 0000 0100 0404 0000
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0030:  0000 0000

unknown packets are coming

I've set a multicast rule to accept:

# set firewall name WAN_LOCAL rule 30 action accept
# set firewall name WAN_LOCAL rule 30 description 'Allow modem multicast traffic'
# set firewall name WAN_LOCAL rule 30 destination address 224.0.0.0/4
# set firewall name WAN_LOCAL rule 30 protocol all

commited changes and save, but iptables statistics gives nothing:

~$ sudo iptables -L -v -n -x

Chain WAN_LOCAL (1 references)
    pkts      bytes target     prot opt in     out     source               destination
14626121 3872633460 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* WAN_LOCAL-10 */ state RELATED,ESTABLISHED
    9257   544684 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* WAN_LOCAL-20 */ state INVALID
       0        0 RETURN     all  --  *      *       0.0.0.0/0            224.0.0.0/4          /* WAN_LOCAL-30 */
      48     2592 LOG        all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* WAN_LOCAL-999 */ LOG flags 0 level 4 prefix "[WAN_LOCAL-999-D]"
      48     2592 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* WAN_LOCAL-999 */
 1684642 86536818 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* WAN_LOCAL-10000 default-action drop */

looks like it is not an ip packet but ether instead

~$ sudo tcpdump -i eth0 -n -e -XX ether multicast
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
19:25:49.811001 00:24:45:62:9b:bb > 01:80:c2:00:00:02, ethertype Slow Protocols (0x8809), length 66: unknown (10), length 52
    0x0000:  0a00 19a7 0001 1000 0000 0100 0404 0000
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0030:  0000 0000
    0x0000:  0180 c200 0002 0024 4562 9bbb 8809 0a00  .......$Eb......
    0x0010:  19a7 0001 1000 0000 0100 0404 0000 0000  ................
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000  ................
    0x0030:  0000 0000 0000 0000 0000 0000 0000 0000  ................
    0x0040:  0000                                     ..
19:25:50.812012 00:24:45:62:9b:bb > 01:80:c2:00:00:02, ethertype Slow Protocols (0x8809), length 66: unknown (10), length 52
    0x0000:  0a00 19a7 0001 1000 0000 0100 0404 0000
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
    0x0030:  0000 0000
    0x0000:  0180 c200 0002 0024 4562 9bbb 8809 0a00  .......$Eb......
    0x0010:  19a7 0001 1000 0000 0100 0404 0000 0000  ................
    0x0020:  0000 0000 0000 0000 0000 0000 0000 0000  ................
    0x0030:  0000 0000 0000 0000 0000 0000 0000 0000  ................
    0x0040:  0000                                     ..

Googling ethertype 0x8809 gives me a link to the telekom document https://www.telekom.de/dlp/agb/pdf/53372.pdf
this is seems to be about EthernetConnect 2.0 - the service available for Geschäftskunden
My question is: is it normal to have discards on the interface?
Just curious if everything is configured right on uplink devices and i should just use my internet and do not pay attention to this discarded packets.