dnsmasq runs the dhcp-script on a renewal only with script-on-renewal, so a pair loaded at the first lease timed out while the lease kept renewing and the bridge table dropped the container's traffic. Set script-on-renewal, time pairs out remaining + 300s, default antiSpoof to log, and run the vm test through renewals with drop.
A forward chain in the hive-owned nft table logs each new flow from the agent bridge to the uplink (v4 and v6) and counts every packet. It never blocks. The mesh interface is skipped. Logging is rate limited per source address; a flow that limit cannot log gets one line from a shared limit with its own prefix. services.hyperhive.network.egress.forward selects accept, log (default) or drop; drop is refused at evaluation until the interception it needs exists.