A friend of mine mentioned that both our Canadian ASNs were listed in AS147028's peer list on https://bgp.he.net/AS147028 but we have no adjacency to this network.
Their peer count jumped from 1 in May 2022 to 1,800 and just a few days ago jumped to 8,800. Beside NL-IX, all the IX they are listed on are virtual IX with a few dozen "hobby networks".
The only lead I have is they use HE as transit and they're pumping back BGP feed to route collectors like RIPE RIS or Route Views with routes stripped of HE's ASN.
Eric