Thanks for the ping, my friend.
Indeed, there was an ISO which was stolen from a customer of ours back in 2017 or 2018 (I think 2017; it was an original 5.0, before 5.0.1) which has made the rounds several times through the warez sites and such. ISTR it hitting eBay a while back, too.
I have learned not to jump the gun, so I've asked the seller (in Italy, apparently) whether this is his personal license or whether he is a "vendor." It may be a one-time user who just didn't like it for some reason and now wants to sell (transfer, in our parlance) his license to someone else. This type of transfer is possible, of course, with our knowledge and consent. Without it, the license becomes null and void, and of course, we have no idea who the new (illegitimate) licensee may be, so he can't possibly renew support or upgrade or even get support in the bugtracker (and yes, we do check serials, and testlog files do have md5sums to warn about alteration).
We'll see where this goes.
Thanks for reporting this, Chris.