Duplicate LAN MAC address on RB750Gr3/OpenWrt 21.02

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1

Device: RB750Gr3
OpenWrt: 21.02.0-rc1 and 21.02-SNAPSHOT r16053-f066ee2ad5 (clean flash)

The kernel log has several lines of the following

br-lan: received packet on lan2 with own address as source address (addr:08:55:31:2e:c0:34, vlan:0)

/etc/config/network

config interface 'loopback'
        option ifname 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option packet_steering '1'
        option ula_prefix 'fd60:2450:7cfe::/48'

config interface 'lan'
        option type 'bridge'
        option ifname 'lan2 lan3 lan4 lan5'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'

config device 'lan_lan2_dev'
        option name 'lan2'
        option macaddr '08:55:31:2e:c0:34'

config device 'lan_lan3_dev'
        option name 'lan3'
        option macaddr '08:55:31:2e:c0:34'

config device 'lan_lan4_dev'
        option name 'lan4'
        option macaddr '08:55:31:2e:c0:34'

config device 'lan_lan5_dev'
        option name 'lan5'
        option macaddr '08:55:31:2e:c0:34'
                                          
config interface 'wan'
        option ifname 'wan'
        option proto 'dhcp'
                                          
config device 'wan_wan_dev'
        option name 'wan'
        option macaddr '08:55:31:2e:c0:33'
                                          
config interface 'wan6'
        option ifname 'wan'
        option proto 'dhcpv6'

br-lan    Link encap:Ethernet  HWaddr 08:55:31:2E:C0:34  
          inet addr:192.168.1.1  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fd60:2450:7cfe::1/60 Scope:Global
          inet6 addr: fe80::a55:31ff:fe2e:c034/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:7817848 errors:0 dropped:10221 overruns:0 frame:0
          TX packets:29839193 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2268222413 (2.1 GiB)  TX bytes:41762819433 (38.8 GiB)

eth0      Link encap:Ethernet  HWaddr 9A:1F:25:A7:ED:85  
          inet6 addr: fe80::981f:25ff:fea7:ed85/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1504  Metric:1
          RX packets:48999305 errors:0 dropped:727 overruns:0 frame:0
          TX packets:49649861 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:58966632988 (54.9 GiB)  TX bytes:59013155965 (54.9 GiB)
          Interrupt:22 

lan2      Link encap:Ethernet  HWaddr 08:55:31:2E:C0:34  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:8713082 errors:0 dropped:0 overruns:0 frame:0
          TX packets:37731810 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2955609938 (2.7 GiB)  TX bytes:53432122200 (49.7 GiB)

lan3      Link encap:Ethernet  HWaddr 08:55:31:2E:C0:34  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:366006 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1086260 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:76602471 (73.0 MiB)  TX bytes:320690756 (305.8 MiB)

lan4      Link encap:Ethernet  HWaddr 08:55:31:2E:C0:34  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:554057 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1952930 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:128542489 (122.5 MiB)  TX bytes:1572504167 (1.4 GiB)

lan5      Link encap:Ethernet  HWaddr 08:55:31:2E:C0:34  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:4458 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4458 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:388570 (379.4 KiB)  TX bytes:388570 (379.4 KiB)

wan       Link encap:Ethernet  HWaddr 08:55:31:2E:C0:33  
          inet6 addr: fe80::a55:31ff:fe2e:c033/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:39327145 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9010969 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:54915576757 (51.1 GiB)  TX bytes:3305977994 (3.0 GiB)
2

br-lan: received packet on lan2 with own address as source address (addr:08:55:31:2e:c0:34, vlan:0)

You don't have a br-lan interface (from an older log file maybe?), but at a guess, your option macaddr for lan2, lan3, lan4, and lan5 all are the same. If something moves from lan2 to lan3, the MAC addresses for that port are identical and it reads it as a loop. (Sender and Destination MACs are the same)