I think your find the reason they see the pinging is because there JJ2 client uses Contrabandent. For the last 4 or so days, the output from it was very buggy, seemed to include a list of servers that werent hosted anymore, with funky version numbers and even some funky ports.

I had a quick look at it now and the bug seems to have cleared itself up, so it should be fine for now, but that could explain why they saw a load of pinging servers in the past.