Hello,
You forgot to allow ARP in Your filter and I reckon that all Your devices on this VLAN are actually not able to communicate hence all counters except VoIP-ICMP are zeros. As for VoIP-ICMP, this term did allow ICMPv6 (which is equivalent to IPv4 ARP) and it seems that You are getting only short ICMPv6 packets 15744/192=82 Bytes/packet.
Please add the following line to Your filter, re-test and report back:
set firewall family ethernet-switching filter VoIP term ARP from ether-type arp then accept
HTH
Thx
Alex