Running udpbroadcastrelay causes strange ARP entries

[t-dubbb]

I am running this on Arch Linux on a firewall appliance. There is an interface named "lan" that has 2 VLANs on it, lan.20 and lan.30, configured with systemd-networkd. I am running 2 instances of the program, one on port 1900 and another on port 5353. Here are the parameters:

/usr/local/bin/udpbroadcastrelay --id 2 --port 5353 --dev lan.20 --dev lan.30 --multicast 224.0.0.251 -s 1.1.1.1 --msearch dial
/usr/local/bin/udpbroadcastrelay --id 1 --port 1900 --dev lan.20 --dev lan.30 --multicast 239.255.255.250 --msearch dial -s 1.1.1.2

This is working OK, I can cast from my iphone on lan.20 to an LG TV on lan.30. However, after starting either or both of the instances, I get 2 FAILED ARP entries. The 2 entries are for the local router IP addresses on lan.20 and lan.30. Below is "ip neigh"

172.16.16.145 dev lan.20 FAILED
172.16.16.1 dev lan.30 FAILED

Whats weirder is that the addresses are flipped; on the system the lan.20 interface is 172.16.16.1 and the lan.30 interface is 172.16.16.145. This isn't causing any connectivity issues but the router is sending ARP requests every second for 172.16.16.145. Shown below is a tcpdump of the ARP requests:

10:05:05.468169 ARP, Request who-has 172.16.16.145 tell 172.16.16.1, length 46

I have no idea what is going on here... all I know is that when I kill both of the udpbroadcastrelay processes and restart systemd-networkd the ARP entries disappear and stay disappeared...... Ideas?