No, my instance (discuss.online) has defederated from lemmygrad.ml but not hexbear.net or lemmy.ml and yet I see the former two but not the latter, so it definitely is something special wrt just it alone.
Also with the URL being to lemmyverse.net, I don’t see how it would even know which instance is “mine”? e.g. I have an alt on startrek.website, which does not block any of those three instances, and another old one on Kbin, but how would it pick?
I suspect rather that there was a network hiccup or other problem obtaining the activity data. But in any case, it’s not like “activity of lemmy.world > activity of lemmy.ml”, and rather more that the latter is unknown to that website.
Btw I nominated your discussion to the BestOf community at lemmy.world/post/16213730 - since you cannot do that yourself, someone else needs to nominate it for you. I hope that helps spread the word some more bc this is a very valuable discussion that needs to happen imho. Thank you for your efforts to improve things for many people in the Fediverse:-).