PFSync traffic in netflow reported on WAN

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Weirdly, reporting reports almost no traffic on my pfsync interface, but reports protocol pfsync and destination ip 224.0.0.240 traffic on WAN.
Now if I tcpdump on both of those, the pfsync traffic clearly uses the right interface.

I don't think the interface order is switched, because apart from that, both interfaces reports look more or less recognizable.

Any ideas?