AX86U_Pro packet flood

[pedeb04]

Looking at my firewall logs on my Ubuntu Desktop - tail /var/log/ufw.log (ufw uncomplicate firewall)
The log file is getting flooded with:

2025-08-23T11:01:39.285489+10:00 nuc kernel: [UFW BLOCK] IN=enp114s0 OUT= MAC=01:00:5e:00:00:01:c8:7f:54:e6:37:08:08:00 SRC=192.168.50.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=36280 DF PROTO=2
2025-08-23T11:01:59.285568+10:00 nuc kernel: [UFW BLOCK] IN=enp114s0 OUT= MAC=01:00:5e:00:00:01:c8:7f:54:e6:37:08:08:00 SRC=192.168.50.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=54719 DF PROTO=2
2025-08-23T11:02:19.285412+10:00 nuc kernel: [UFW BLOCK] IN=enp114s0 OUT= MAC=01:00:5e:00:00:01:c8:7f:54:e6:37:08:08:00 SRC=192.168.50.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=57096 DF PROTO=2
2025-08-23T11:02:39.286251+10:00 nuc kernel: [UFW BLOCK] IN=enp114s0 OUT= MAC=01:00:5e:00:00:01:c8:7f:54:e6:37:08:08:00 SRC=192.168.50.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=61385 DF PROTO=2
2025-08-23T11:02:59.286461+10:00 nuc kernel: [UFW BLOCK] IN=enp114s0 OUT= MAC=01:00:5e:00:00:01:c8:7f:54:e6:37:08:08:00 SRC=192.168.50.1 DST=224.0.0.1 LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=7852 DF PROTO=2

I can stop it with

peter@nuc:~$ sudo ufw deny from 192.168.50.1 to 224.0.0.1

But I don't understand why it is get transmitted from the router in the first place. It is not causing any issues.
Any clues?