I’ve looked in the DB and as far as i can tell, they triple posted. Each one has a unique AP_id which means that each of those comments was most likely created on the host instance (lemmy.ml) then sent to us an activity, rather than being federated incorrectly. Always happy to check other examples though, i know there has been an issue with lemmy.world duplicating all their activities for some reason (although thankfully it didnt mean we had 2 of everything!)