fix A3 event configuration

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As a reference, for comparison purpose, here are PCAP and TXT files for various tests done in develop and in this MR.

Despite the file names (develop-[...].txt), the TXT config is used in both cases (develop and this-mr).

• develop-2-neigh.pcap this-mr-2-neigh.pcap develop-2-neigh.txt

• develop-default-neigh.pcap this-mr-default-neigh.pcap develop-default-neigh.txt

• develop-nonexistant-neigh.pcap this-mr-nonexistant-neigh.pcap develop-nonexistant-neigh.txt